Mesorhizobium Ciceri Research Articles

SCREENING OF MODERN CHICKPEA VARIETIES BY RESPONSE TO BACTERIZATION

Objective. To screen modern varieties of chickpeas of Ukrainian selection by the response to bacterization, to identify varieties characterized by high increases in symbiotic activity and yield. Methods. Biotesting, gas-chromatographic, field experiment, statistical. Results. The response to bacterization of chickpea seeds of different varieties was studied in a field experiment in the southern region of Ukraine (Region of Odesa). As a result of inoculation of chickpea seeds with a bacterial suspension of an effective strain of Mesorhizobium ciceri ND-64, a significant increase in nodulation activity was registered. The highest increase in the number of nodules (51.6 % and 53 %) was reported for the varieties Odysei and Triumf. Upon seed inoculation with the studied strain, a significant increase in the weight of nodules of the Triumf variety (2.3 times) was shown. In the control variants, the nitrogenase activity in the nodules of Skarb variety plants was the highest (425 nmol C2H4/plant per hour), and in the Budzhak variety it was the lowest (159 nmol C2H4/plant per hour). Inoculation of seeds with bacterial suspension of M. ciceri ND-64 contributed to a significant increase in the studied parameter in the varieties Budzhak, Pamiat, Odysei and Triumf. The latter was characterized by the most significant response to inoculation with an effective strain in terms of nodulation and nitrogenase activity. Symbiotic parameters showed the weakest ability to respond to inoculation in terms of symbiotic parameters in Skarb variety. Pamiat variety was characterised by the maximum number of seeds per plant (18.5 units/plant). However, as a result of inoculation of chickpea seeds with M. ciceri ND-64, the number of seeds increased the most in the variety Skarb and amounted to 28.7 units/plant. In terms of seed weight, the Triumph variety was superior (9.5 g/plant). The yield of all studied varieties of chickpeas after bacterization of seeds with M. ciceri ND-64 significantly exceeded the control variants (without inoculation) by 21–56 %. The highest increase in control was observed for the varieties Triumph (0.49 t/ha) and Skarb (0.56 t/ha). The ability of nodule bacteria M. ciceri ND-64 to intensive synthesis of phytohormones and the formation of highly effective symbiosis with chickpea plants of different varieties provided a complementary interaction of rhizobia with plants and a significant increase in crop yield. Conclusion: Due to the interaction with aboriginal nodule bacteria, the highest parameters of nodulation and nitrogenase activity were typical for the varieties Triumf and Skarb, yields for Triumf and Budzhak. Screening of varieties by the response to inoculation with an effective strain of M. ciceri ND-64 indicates an increase in symbiotic activity in varieties Triumf, Budzhak (large-seeded), Pamiat (medium-seeded). The maximum increase in yield as a result of inoculation was found in chickpea varieties Skarb and Triumf. M. ciceri ND-64 are capable of active synthesis of substances of phytohormonal nature, which contributes to the effective interaction between rhizobia and chickpea plants.

Mesorhizobium ciceri as biological tool for improving physiological, biochemical and antioxidant state of Cicer aritienum (L.) under fungicide stress

Fungicides among agrochemicals are consistently used in high throughput agricultural practices to protect plants from damaging impact of phytopathogens and hence to optimize crop production. However, the negative impact of fungicides on composition and functions of soil microbiota, plants and via food chain, on human health is a matter of grave concern. Considering such agrochemical threats, the present study was undertaken to know that how fungicide-tolerant symbiotic bacterium, Mesorhizobium ciceri affects the Cicer arietinum crop while growing in kitazin (KITZ) stressed soils under greenhouse conditions. Both in vitro and soil systems, KITZ imparted deleterious impacts on C. arietinum as a function of dose. The three-time more of normal rate of KITZ dose detrimentally but maximally reduced the germination efficiency, vigor index, dry matter production, symbiotic features, leaf pigments and seed attributes of C. arietinum. KITZ-induced morphological alterations in root tips, oxidative damage and cell death in root cells of C. arietinum were visible under scanning electron microscope (SEM). M. ciceri tolerated up to 2400 µg mL−1 of KITZ, synthesized considerable amounts of bioactive molecules including indole-3-acetic-acid (IAA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, siderophores, exopolysaccharides (EPS), hydrogen cyanide, ammonia, and solubilised inorganic phosphate even in fungicide-stressed media. Following application to soil, M. ciceri improved performance of C. arietinum and enhanced dry biomass production, yield, symbiosis and leaf pigments even in a fungicide-polluted environment. At 96 µg KITZ kg−1 soil, M. ciceri maximally and significantly (p ≤ 0.05) augmented the length of plants by 41%, total dry matter by 18%, carotenoid content by 9%, LHb content by 21%, root N by 9%, shoot P by 11% and pod yield by 15% over control plants. Additionally, the nodule bacterium M. ciceri efficiently colonized the plant rhizosphere/rhizoplane and considerably decreased the levels of stressor molecules (proline and malondialdehyde) and antioxidant defence enzymes viz. ascorbate peroxidise (APX), guaiacol peroxidise (GPX), catalase (CAT) and peroxidises (POD) of C. arietinum plants when inoculated in soil. The symbiotic strain effectively colonized the plant rhizosphere/rhizoplane. Conclusively, the ability to endure higher fungicide concentrations, capacity to secrete plant growth modulators even under fungicide pressure, and inherent features to lower the level of proline and plant defence enzymes makes this M. ciceri as a superb choice for augmenting the safe production of C. arietinum even under fungicide-contaminated soils.

Large-scale screening of rhizobacteria to enhance the chickpea-Mesorhizobium symbiosis using a plant-based strategy

Rhizobacteria able to express multiple plant growth-promoting (PGP) traits has been frequently failed to enhance the chickpea-Mesorhizobium symbiosis possibly because a relatively large amount of organic acids exudated by chickpea root to form an acid rhizosphere reduced the survival and colonisation of plant growth-promoting rhizobacteria (PGPR). Therefore, this study was initiated to screen rhizobacteria that would enhance the chickpea-Mesorhizobium symbiosis using a plant-basedstrategyA total of 743 Bacillus-, Burkholderia- and Pseudomonas-like bacteria were isolated from 74 agricultural soil samples collected across Australia. Only 167 isolates were selected, based upon their individual performance in a seedling growth bioassay, to test their effect on nodulation and growth of chickpea in sterile growth pouches. Also, their ability to produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase and indole acetic acid (IAA) was investigated in relation to their mode of action. The diversity of the 167 isolates was investigated using 16S rDNA sequencing. Of 743 isolates, 697 (83%) were able to produce IAA in the presence of L-tryptophan. ACC deaminase production was detected in 57 isolates (7.7%). Commercial inoculant strain Mesorhizobium ciceri CC1192 produced 7 μg mL−1 IAA and lacked ACC deaminase activity. In further investigation, the promotion of seedling root elongation by rhizobacteria predicted their effect on nodulation and growth of chickpea after dual inoculation in aseptic conditions. The effect of rhizobacteria on seedling root growth as well as shoot growth and nodulation was associated with the capacity of the isolates to produce IAA and ACC deaminase. These isolates were superior in plant growth promotion than those PGPR unable to produce PGP traits. The synthesis of IAA along with ACC deaminase activity by rhizobacteria gave an added advantage in promoting the ability of rhizobia to form an efficient chickpea-Mesorhizobium symbiosis as measured by biomass production and nodulation. Most of these rhizobacteria belonged to the genus Burkholderia. The use of a plant-based first-stage screening strategy in combination with assays for in vitro production of IAA and ACC deaminase enabled the identification of efficient PGPR that were able to enhance the legume-rhizobia symbiosis.

Co-Inoculation of Mesorhizobium ciceri with Either Bacillus sp. or Enterobacter aerogenes on Chickpea Improves Growth and Productivity in Phosphate-Deficient Soils in Dry Areas of a Mediterranean Region.

Biological nitrogen fixation requires a large amount of phosphorus (P). However, most of the soils are P-deficient and the extensive use of P- chemical fertilizers constitute a serious threat to the environment. In this context, two field experiments were carried out to investigate the effect of co-inoculation of Mesorhizobium ciceri with phosphate solubilizing bacteria (PSB), Bacillus sp., and Enterobacter aerogenes, on chickpea as an alternative to chemical nitrogen (N) and phosphorous fertilizers in P-deficient soils in dry areas of Morocco. The results revealed that combined inoculation of chickpea with rhizobia and PSB showed a significant enhancement of chickpea nodulation, biomass production, yields and N, P, and protein content in grains as compared to single inoculation or single application of N or P. A significantly higher increase was obtained by inoculating chickpea with Mesorhizobium sp. MA72 combined with E. aerogenes P1S6. This combination allowed an enhancement of more than 270% in nodulation, 192% in shoot dry weight and 242% in grain yield. The effect of this combination was equivalent to the effect of combined application of N and P fertilizers. Formulation of biofertilizers based on tasted strains could be used for chickpea co-inoculation in P-deficient soils for an eco-friendly sustainable production of chickpea.

Study of symbiotic nitrogen fixation of chickpea (Cicer arietinum L.) in the Oryol region

Modern agriculture tends to reduce chemogenic loads on the environment and becomes more environmentally oriented. In this regard, increasing the yield of agricultural crops through the use of useful soil microflora is an urgent direction in research. In the field conditions of the Oryol region, the features of the formation and operation of symbiotic systems of 13 chickpea varieties under mono - and double inoculation with different strains of nitrogen-fixing bacteria Mesorhizobium ciceri and a soil-root mixture containing a mix of arbuscular mycorrhizal fungi Glomus spp were studied. The use of microbiological drugs had a positive effect on the growth and development of most chickpea varieties, which contributed to a more intensive accumulation of green mass of plants, led to an increase in the duration of the growing season by 1…7 days compared to the control. At the same time, the plants exceeded the control by 0.5…23.4% in height. There was an increase in the weight of dry plants by 0.7…70.1%, the number of seeds per plant by 0.3…69.1%, the weight of seeds per plant by 0.6…71.4%, and the weight of 1000 seeds by 0.4…36.9%. It was found that the most powerful and active symbiotic apparatus in chickpeas is formed during the flowering period – the beginning of bean formation. The maximum number of nodules was formed in the Avatar variety in the variant with mono inoculation of Mesorhizobium ciceri strain 065 and in the Krasnokutsky 123 variety in the variant with Mesorhizobium ciceri strains 527 and 522. The highest values of nitrogenase activity (109.23…155.79 mg N2/plant h) were recorded in the varieties Avatar, Krasnokutsky 123 and Kostyuzhansky 27 in the variants with double inoculation.

Evolution of diverse effective N2-fixing microsymbionts of Cicer arietinum following horizontal transfer of the Mesorhizobium ciceri CC1192 symbiosis integrative and conjugative element.

Rhizobia are soil bacteria capable of forming N2-fixing symbioses with legumes, with highly effective strains often selected in agriculture as inoculants to maximize symbiotic N2 fixation. When rhizobia in the genus Mesorhizobium have been introduced with exotic legumes into farming systems, horizontal transfer of symbiosis Integrative and Conjugative Elements (ICEs) from the inoculant strain to soil bacteria has resulted in the evolution of ineffective N2-fixing rhizobia that are competitive for nodulation with the target legume. In Australia, Cicer arietinum (chickpea) has been inoculated since the 1970's with Mesorhizobium ciceri sv. ciceri CC1192, a highly effective strain from Israel. Although the full genome sequence of this organism is available, little is known about the mobility of its symbiosis genes and the diversity of cultivated C. arietinum-nodulating organisms. Here, we show the CC1192 genome harbors a 419-kb symbiosis ICE (ICEMcSym1192) and a 648-kb repABC-type plasmid pMC1192 carrying putative fix genes. We sequenced the genomes of 11 C. arietinum nodule isolates from a field site exclusively inoculated with CC1192 and showed they were diverse unrelated Mesorhizobium carrying ICEMcSym1192, indicating they had acquired the ICE by environmental transfer. No exconjugants harboured pMc1192 and the plasmid was not essential for N2 fixation in CC1192. Laboratory conjugation experiments confirmed ICEMcSym1192 is mobile, integrating site-specifically within the 3' end of one of the four ser-tRNA genes in the R7ANS recipient genome. Strikingly, all ICEMcSym1192 exconjugants were as efficient at fixing N2 with C. arietinum as CC1192, demonstrating ICE transfer does not necessarily yield ineffective microsymbionts as previously observed.Importance Symbiotic N2 fixation is a key component of sustainable agriculture and in many parts of the world legumes are inoculated with highly efficient strains of rhizobia to maximise fixed N2 inputs into farming systems. Symbiosis genes for Mesorhizobium spp. are often encoded chromosomally within mobile gene clusters called Integrative and Conjugative Elements or ICEs. In Australia, where all agricultural legumes and their rhizobia are exotic, horizontal transfer of ICEs from inoculant Mesorhizobium strains to native rhizobia has led to the evolution of inefficient strains that outcompete the original inoculant, with the potential to render it ineffective. However, the commercial inoculant strain for Cicer arietinum (chickpea), M. ciceri CC1192, has a mobile symbiosis ICE (ICEMcSym1192) which can support high rates of N2 fixation following either environmental or laboratory transfer into diverse Mesorhizobium backgrounds, demonstrating ICE transfer does not necessarily yield ineffective microsymbionts as previously observed.

MESORHIZOBIUM CICERІ ND-64 STRAIN — EFFECTIVE MICROSYMBIONT OF MODERN CHICKPEA VARIETIES

Objective. Study the competitiveness, complementarity and symbiotic activity of a new strain of chickpea nodule bacteria Mesorhizobium ciceri ND-64, study the influence of seed inoculation on the productivity and yield of chickpea varieties of Ukrainian selection under their cultivation in different soil and climatic zones of Ukraine. Methods. Serological, gas chromatography, field experiment and statistical. Results. The use of a new strain of M. ciceri ND-64 for pre-sowing bacterization of chickpea seeds of varieties Skarb, Admiral, Odysei, Budzhak, Triumf and Pamiat upon growing in field experiments in the Steppe zone against the background of the local population of nodule bacteria contributes to a significant increase in nitrogen-fixing nodules by 5 % to 67 %, an increase in the mass of nodules by 10 % to 67 % and nitrogenase activity 26 % to 150 % compared with the positive control (inoculation with the reference strain of M. ciceri H-12). The use of M. ciceri ND- 64 for pre-sowing bacterization of chickpea seeds under cultivation in the Steppe zone of Ukraine also had a positive effect on increasing the yield of chickpea — by 4 % to 18 % compared to the positive control. Inoculation with a new strain of chickpea seeds of varieties Skarb, Triumf and Pamiat contributed to the formation of higher number of nodules (by 57 % to 89 %), increaseed mass of nodules (2.2–2.9 times) and their nitrogenase activity (2–4 times) compared with the positive control upon cultivation in the Polissia zone on the fields where there is no population of chickpea rhizobia. Under these conditions, an increase in structural parameters of yield, the highest gain in chickpea yield, increase in photosynthetic activity and protein content in grain upon inoculation with M. ciceri ND-64 was shown. Obtaining a specific antisera by immunization of rabbits allowed to detect serological relatedness of M. ciceri ND-64, M. ciceri H-101, Mesorhizobium sp. ND-601 and M. ciceri ND-64, isolated from chickpea nodules of Skarb and Pamiat varieties. The competitiveness of M. ciceri ND-64 was determined using the immunological method in the field experiment. It was found that 100 % of nodules have been formed by the representatives of M. ciceri ND-64 in the variant where this serological group was applied for inoculation in the variant with inoculation of the strain M. ciceri ND-64 100 % of the nodules were formed by representatives of this serogroup. Conclusion. M. ciceri ND-64 strain is an effective microsymbiont of chickpea plants, due to its virulence, competitiveness, nitrogen-fixing properties. According to the results of field experiments, it was shown that the new strain, complementary to all studied varieties differing in seed size and shape, type of bush and average height, forms an effective symbiosis for growing chickpea plants both against the active local population of rhizobia and upon the absence of M. cicerі population in the soil. Symbiotic parameters upon seed treatment with suspension of M. ciceri ND-64 exceed these values in the variants with inoculation using the reference strain of M. ciceri H-12 and strains isolated from the nodules of each study variety. Therefore, M. ciceri ND-64 can be used as a bioagent of a microbial preparation for inoculation of chickpea of different varieties in order to form an effective bean-rhizobial symbiosis, increase the productivity of this culture and improve seed quality.

MESORHIZOBIUM CICERІ ND-64 STRAIN — EFFECTIVE MICROSYMBIONT OF MODERN CHICKPEA VARIETIES

Objective. Study the competitiveness, complementarity and symbiotic activity of a new strain of chickpea nodule bacteria Mesorhizobium ciceri ND-64, study the influence of seed inoculation on the productivity and yield of chickpea varieties of Ukrainian selection under their cultivation in different soil and climatic zones of Ukraine. Methods. Serological, gas chromatography, field experiment and statistical. Results. The use of a new strain of M. ciceri ND-64 for pre-sowing bacterization of chickpea seeds of varieties Skarb, Admiral, Odysei, Budzhak, Triumf and Pamiat upon growing in field experiments in the Steppe zone against the background of the local population of nodule bacteria contributes to a significant increase in nitrogen-fixing nodules by 5 % to 67 %, an increase in the mass of nodules by 10 % to 67 % and nitrogenase activity 26 % to 150 % compared with the positive control (inoculation with the reference strain of M. ciceri H-12). The use of M. ciceri ND- 64 for pre-sowing bacterization of chickpea seeds under cultivation in the Steppe zone of Ukraine also had a positive effect on increasing the yield of chickpea — by 4 % to 18 % compared to the positive control. Inoculation with a new strain of chickpea seeds of varieties Skarb, Triumf and Pamiat contributed to the formation of higher number of nodules (by 57 % to 89 %), increaseed mass of nodules (2.2–2.9 times) and their nitrogenase activity (2–4 times) compared with the positive control upon cultivation in the Polissia zone on the fields where there is no population of chickpea rhizobia. Under these conditions, an increase in structural parameters of yield, the highest gain in chickpea yield, increase in photosynthetic activity and protein content in grain upon inoculation with M. ciceri ND-64 was shown. Obtaining a specific antisera by immunization of rabbits allowed to detect serological relatedness of M. ciceri ND-64, M. ciceri H-101, Mesorhizobium sp. ND-601 and M. ciceri ND-64, isolated from chickpea nodules of Skarb and Pamiat varieties. The competitiveness of M. ciceri ND-64 was determined using the immunological method in the field experiment. It was found that 100 % of nodules have been formed by the representatives of M. ciceri ND-64 in the variant where this serological group was applied for inoculation in the variant with inoculation of the strain M. ciceri ND-64 100 % of the nodules were formed by representatives of this serogroup. Conclusion. M. ciceri ND-64 strain is an effective microsymbiont of chickpea plants, due to its virulence, competitiveness, nitrogen-fixing properties. According to the results of field experiments, it was shown that the new strain, complementary to all studied varieties differing in seed size and shape, type of bush and average height, forms an effective symbiosis for growing chickpea plants both against the active local population of rhizobia and upon the absence of M. cicerі population in the soil. Symbiotic parameters upon seed treatment with suspension of M. ciceri ND-64 exceed these values in the variants with inoculation using the reference strain of M. ciceri H-12 and strains isolated from the nodules of each study variety. Therefore, M. ciceri ND-64 can be used as a bioagent of a microbial preparation for inoculation of chickpea of different varieties in order to form an effective bean-rhizobial symbiosis, increase the productivity of this culture and improve seed quality.

Dynamics of formation and functioning of legume-rhizobial symbiosis Mesorhizobium ciceri-Cicer arietinum (variety Pam'iat')

The study of the dynamics of formation and functioning of symbiosis between nodule bacteria and chickpea plants was carried out in the northern region of Ukraine in the experimental plots, where the local population of chickpea mesorhizobia began to form. A new strain of Mesorhizobium ciceri ND-64 and a reference Mesorhizobium ciceri H-12 were used to inoculate Cicer arietinum seeds. The field study determined the number, weight, nitrogenase activity of nodules on the chickpea roots, dry green mass and mass of roots of chickpea plants of Pam'iat' variety. Samplings were carried out nine times in different phases of plant vegetation, starting from the branching phase and ending with the phase of complete maturity of seeds. The study showed that round and oval nodules appeared on the roots of chickpea plants during the branching stage. Gradually, they increased in size and in the phase of budding formed splices. The largest number of nodules (43.1 units/plant) was formed in the bean formation phase. The highest nitrogenase activity of the nodules was registered in the flowering phase. It was found that the bacterization of M. ciceri ND-64 promotes earlier formation and long-term functioning of the symbiotic apparatus in comparison with the reference strain and the control variant. The highest symbiotic rates under inoculation with M. ciceri ND-64 were registered at the beginning of the bean formation phase. In the control variant and with inoculation of M. ciceri H-12, these parameters were the highest later (at the end of the bean formation phase) and rapidly decreased in the subsequent phases, while the nodules formed by M. ciceri ND-64 continued to functioning actively. The positive effect of inoculation of chickpea seeds with a suspension of M. ciceri ND-64 on the increase in the number of beans and seeds per plant, weight of 1000 seeds and yield of chickpea plants was shown. Considering the obtained data, the new strain M. ciceri ND-64 is a promising bioagent of a microbial preparation for bacterization of chickpea

Siirt Ekolojik Koşullarında Mikrobiyolojik ve İnorganik Gübrelemenin Nohut (Cicer arietinum l.)’un Kalite Özellikleri Üzerine Etkileri

Siirt ekolojik koşullarında mikrobiyolojik ve inorganik gübrelemenin nohut (Cicer arietinum L.)’ un verim, verim öğeleri ve nodülasyonu üzerine etkilerini belirlemek amacıyla yapılan bu çalışma tesadüf bloklarında faktöriyel deneme deseninde 3 tekerrürlü olarak 2016-2017 ve 2017-2018 yılları arasında yürütülmüştür. Çalışmada simbiyotik bakteri olarak Mesorhizobium ciceri, asimbiyotik bakteri olarak azot bağlayıcı Basillus atrophaeus, fosfat çözücü olarak Basillus GC-group ve inorganik gübre olarak DAP gübresi kullanılmıştır. Araştırmada; tane protein oranı, protein verimi, tane fosfor içeriği, tane potasyum içeriği, tane nem oranı ve tanede toplam kuru madde oranı özellikleri incelenmiştir. Çalışmadan elde edilen bulgulara göre, tane protein oranı %22.3-25.6, protein verimi 21.2-40.4 kg/da, tane fosfor içeriği %0.43-0.71, tane potasyum içeriği %0.96-1.58, tane nem oranı %4.02-6.01 ve tanede toplam kuru madde oranı %93.98-95.97 arasında değişim göstermiştir. Çalışmada en yüksek protein içeriği, Mesorhizobium ciceri + %50 DAP ve Bacillus atrophaeus (N) + %50 DAP uygulamaları ile elde edilmiştir. Sonuç olarak, mikrobiyolojik gübre kullanımının inorganik gübrelere tamamen bir alternatif olmamasına rağmen kullanım miktarının azalmasına olanak sağladığı tespit edilmiştir.

Farklı Sıra Arası Mesafeleri, Tavuk Gübresi Dozları Ve Tohum Ön Uygulamalarının Nohut (Cicer arietinum L.)’Un Verim Ve Verim Özellikleri Üzerine Etkileri

Farklı sıra arası mesafeleri, tavuk gübresi dozları ve tohum ön uygulamalarının nohut (Cicer arietinum L.)’un verim ve verim özellikleri üzerine etkilerini belirlemek amacıyla yapılan bu çalışma, 2016 ve 2017 yetiştirme sezonunda Siirt koşullarında yürütülmüştür. Denemeler bölünen bölünmüş parseller deneme deseninde 3 tekerrürlü olarak kurulmuştur. Araştırmada 20, 30 ve 40 cm olmak üzere 3 farklı sıra arası mesafe ana parsellere; tohum ön uygulaması ve Mesorhizobium ciceri aşılama alt parsellere; tavuk gübresi dozları 0, 40, 120 ve 200 kg/da hesabına göre altın altı parsellere uygulanmıştır. Bu çalışmanın sonuçlarına göre; bitki boyu 54.4-66.0 cm, ilk bakla yüksekliği 29.5-36.7 cm, bitkide bakla sayısı 29.3-43.9 adet/bitki, bitkide tane sayısı 29.4-44.9 adet/bitki, 100-tane ağırlığı 30.1-36.2 g ve tane verimi 83.4-253.7 kg/da değerleri arasında değişim göstermiştir. Sıra arası mesafelerin, ön uygulamaların ve tavuk gübresi dozlarının tane verimine etkileri önemli bulunmuştur. Sıra arası mesafe azaldıkça ve tavuk gübresi dozu arttıkça tane verimi artış göstermiştir. En yüksek tane verimi 190.3 kg/da ile 20 cm sıra arası mesafeden elde edilirken, ön uygulamalardan Mesorhizobium ciceri aşılaması 157.8 kg/da ile en yüksek tane verimini vermiştir. Tavuk gübresi uygulamasında ise 157.7 kg/da ile 200 kg/da dozundan elde edilmiştir. Sonuç olarak, Siirt ili ekolojik koşullarında yürütülen bu çalışmada en yüksek tane verimi 253.7 kg/da ile 20 cm sıra arası mesafe + Mesorhizobium ciceri + 40 kg/da tavuk gübresi uygulamasından elde edilmiştir.

Characterization of genes involved in the autoregulation of nodulation in chickpea (Cicer arietinum L.)

Establishment of an excess number of nodules markedly affects plant growth and development due to overconsumption of photosynthates for nitrogen fixation. Hence, the total root nodule number must be tightly controlled via a negative feedback mechanism (AON) to maintain an optimal nitrogen and carbon balance in chickpea plants. Chickpea genes whichplay important regulatory roles in root nodulation in chickpea (Cicer arietinum) were identified by aligning these genes with known genes of legumes available at phytozome through BLAST search. Chickpea nodulation genes identified and characterized in this study include CaNFR1/5, CaENOD40, CaNARK, CaRIC1, CaRIC2, CaNIC1, CaRDN1, CaRDN2, CaRDN3, CamiRNA172 and CaNNC1. These genes were orthologous to Medicago truncatula nodulation genes and were significantly expressed by inoculating chickpea plants with Mesorhizobium ciceri analysed by qRT-PCR using RNA isolated from the root and leaf tissues of inoculated chickpea plants at 0, 2, and 6 days after inoculation. Non-inoculated plants served as control. CaNARK genes were expressed in roots and leaves while the rest of the nodulation genes were expressed only in the roots. The nodulation ability of chickpea may be controlled by an internal AON mechanism which involves several genes that are orthologues with other legumes.

Desert Soil Microbes as a Mineral Nutrient Acquisition Tool for Chickpea (Cicer arietinum L.) Productivity at Different Moisture Regimes.

Drought is a major constraint in drylands for crop production. Plant associated microbes can help plants in acquisition of soil nutrients to enhance productivity in stressful conditions. The current study was designed to illuminate the effectiveness of desert rhizobacterial strains on growth and net-return of chickpeas grown in pots by using sandy loam soil of Thal Pakistan desert. A total of 125 rhizobacterial strains were isolated, out of which 72 strains were inoculated with chickpeas in the growth chamber for 75 days to screen most efficient isolates. Amongst all, six bacterial strains (two rhizobia and four plant growth promoting rhizobacterial strains) significantly enhanced nodulation and shoot-root length as compared to other treatments. These promising strains were morphologically and biochemically characterized and identified through 16sRNA sequencing. Then, eight consortia of the identified isolates were formulated to evaluate the growth and development of chickpea at three moisture levels (55%, 75% and 95% of field capacity) in a glass house experiment. The trend for best performing consortia in terms of growth and development of chickpea remained T2 at moisture level 1 > T7 at moisture level 2 > T4 at moisture level 3. The present study indicates the vital role of co-inoculated bacterial strains in growth enhancement of chickpea under low moisture availability. It is concluded from the results that the consortium T2 (Mesorhizobium ciceri RZ-11 + Bacillus subtilis RP-01 + Bacillus mojavensis RS-14) can perform best in drought conditions (55% field capacity) and T4 (Mesorhizobium ciceri RZ-11 + Enterobacter Cloacae RP-08 + Providencia vermicola RS-15) can be adopted in irrigated areas (95% field capacity) for maximum productivity of chickpea.

Identification of genes involved in phosphate solubilization and drought stress tolerance in chickpea symbiont Mesorhizobium ciceri Ca181.

Chickpea plant root colonizing bacteria Mesorhizobium ciceri Ca181 promotes plant growth and development through symbiotic association with root nodules. The potentially beneficial effects on plants generated due to this bacterium are mineral nutrient solubilization, abiotic stress tolerance, and nitrogen-fixation, though the molecular mechanisms underlying these probiotic capacities are still largely unknown. Hence, this study aims to describe the molecular mechanism of M. ciceri Ca181 in drought stress tolerance and phosphorus solubilization. Here we have developed the transposon inserted mutant library of strain Ca181 and further screened it to identify the phosphorous solubilization and PEG-induced drought stress tolerance defective mutants, respectively. Resultantly, a total of four and three mutants for phosphorous solubilization and drought stress tolerance were screened and identified. Consequently, Southern blot confirmation was done for the cross verification of insertions and stability in the genome. Through the sequencing of each mutant, the interrupted gene was confirmed, and the finding revealed that the production of gluconic acid is necessary for phosphorus solubilization, whileotsA, Auc, and Usp genes were involved in the mechanism of drought stress tolerance in M. ciceri Ca181.

Phylogeography and Symbiotic Effectiveness of Rhizobia Nodulating Chickpea (Cicer arietinum L.) in Ethiopia

Chickpea (Cicer arietinum L.) used to be considered a restrictive host that nodulated and fixed nitrogen only with Mesorhizobium ciceri and M. mediterraneum. Recent analysis revealed that chickpea can also establish effective symbioses with strains of several other Mesorhizobium species such as M. loti, M. haukuii, M. amorphae, M. muleiense, etc. These strains vary in their nitrogen fixation potential inviting further exploration. We characterized newly collected mesorhizobial strains isolated from various locations in Ethiopia to evaluate genetic diversity, biogeographic structure and symbiotic effectiveness. Symbiotic effectiveness was evaluated in Leonard Jars using a locally released chickpea cultivar “Nattoli”. Most of the new isolates belonged to a clade related to M. plurifarium, with very few sequence differences, while the total collection of strains contained three additional mesorhizobial genospecies associated with M. ciceri, M. abyssinicae and an unidentified Mesorhizobium species isolated from a wild host in Eritrea. The four genospecies identified represented a subset of the eight major Mesorhizobium clades recently reported for Ethiopia based on metagenomic data. All Ethiopian strains had nearly identical symbiotic genes that grouped them in a single cluster with M. ciceri, M. mediterraneum and M. muleiense, but not with M. plurifarium. Some phylogeographic structure was observed, with elevation and geography explaining some of the genetic differences among strains, but the relation between genetic identity and symbiotic effectiveness was observed to be weak.

Order of microbial succession affects rhizobia-mediated biocontrol efforts against Phytophthora root rot

The management of soilborne root diseases in pulse crops is challenged by a limited range of resistance sources and often a complete absence of in-crop management options. Therefore, alternative management strategies need to be developed. We evaluated disease limiting interactions between the rhizobia species Mesorhizobium ciceri, and the oomycete pathogen Phytophthora medicaginis, which causes Phytophthora root rot (PRR) of chickpea (Cicer arietinum). For the PRR susceptible var. Sonali plants, post-pathogen M. ciceri inoculation significantly improved probability of plant survival when compared to P. medicaginis infected plants only pre-inoculated with M. ciceri (75 % versus 35 %, respectively). Potential mechanisms for these effects were investigated: rhizobia inoculation benefits to plant nodulation were not demonstrated, but the highest nodule N-fixation activity of P. medicaginis inoculated plants occurred for the post-pathogen M. ciceri treatment; rhizobia inoculation treatment did not reduce lesion development but certain combinations of microbial inoculation led to significant reduction in root growth. Microcosm studies, however, showed that the presence of M. ciceri reduced growth of P. medicaginis isolates. Putative chickpea disease resistance gene expression was evaluated using qPCR in var. Sonali roots. When var. Sonali plants were treated with M. ciceri post-P. medicaginis inoculation, the gene regulation in the plant host became more similar to PRR moderately resistant var. PBA HatTrick. These results suggest that M. ciceri application post P. medicaginis inoculation may improve plant survival by inducing defense responses similar to a PRR moderately resistant chickpea variety. Altogether, these results indicate that order of microbial succession can significantly affect PRR plant survial in susceptible chickpea under controlled conditions and improved plant survival effects are due to a number of different mechanisms including improved host nutrition, through direct inhibiton of pathogen growth, as well as host defense priming.

Symbiotic interactions between chickpea (Cicer arietinum L.) genotypes and Mesorhizobium strains

Legume genotype (GL) x rhizobium genotype (GR) interaction in chickpea was studied using a genetically diverse set of accessions and rhizobium strains in modified Leonard Jars. A subset of effective GL x GR combinations was subsequently evaluated in a pot experiment to identify combinations of chickpea genotypes and rhizobium strains with stable and superior symbiotic performance. A linear mixed model was employed to analyse the occurrence of GL x GR interaction and an additive main effects and multiplicative interaction (AMMI) model was used to study patterns in the performance of genotype-strain combinations. We found statistically significant interaction in jars in terms of symbiotic effectiveness that was entirely due to the inclusion of one of the genotypes, ICC6263. No interaction was found in a subsequent pot experiment. The presence of two genetic groups (Kabuli and Desi genepools) did not affect interaction with Mesorhizobium strains. With the exception of a negative interaction with genotype ICC6263 in the jar experiment, the type strain Mesorhizobium ciceri LMG 14989 outperformed or equalled other strains on all chickpea genotypes in both jar and pot experiments. Similar to earlier reports in common bean, our results suggest that efforts to find more effective strains may be more rewarding than aiming for identification of superior combinations of strains and genotypes.

Mesorhizobium terrae sp. nov., a novel species isolated from soil in Jangsu, Korea.

A gram-negative, white-pigmented, aerobic, rod-shaped bacterium, designated as strain NIBRBAC000500504T, was isolated from soil in Jangsu, Korea. Optimal growth of this strain was observed at 25 °C, pH 7.0, and in the presence of 0% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NIBRBAC000500504T belonged to the genus Mesorhizobium and was closely related to Mesorhizobium shangrilense LMG 24762T (98.3% sequence similarity), Mesorhizobium australicum LMG 24608T (98.2%), Mesorhizobium qingshengii LMG 26793T (98.1%), Mesorhizobium ciceri ATCC 51585T (98.0%), Mesorhizobium loti DSM 2626T (98.0%), Mesorhizobium sophorae LMG 28223T (97.9%), Mesorhizobium waitakense LMG 28227T (97.8%), and Mesorhizobium cantuariense LMG 28225T (97.8%). Next-generation sequencing analysis indicated that the genome of strain NIBRBAC000500504T comprised a circular chromosome (5,731,152 bp, G+C content: 63.26%) and a plasmid (293,638 bp, G+C content: 61.39%) with 5672 coding sequences, 50 tRNAs, and 6 rRNAs. The major respiratory isoprenoid quinone was Q10; the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine; the major fatty acids were summed feature 8 (comprising C18:1 ω7c/C18:1 ω6c), C19:0 cyclo ω8c, C16:0, and C18:1 ω7c 11-methyl; and the G+C content of the genomic DNA was 62.9 mol%. The DNA-DNA relatedness values between NIBRBAC000500504T and its closest type strains were low. On the basis of these polyphasic taxonomic data, it is proposed that strain NIBRBAC000500504T represents a novel species of the genus Mesorhizobium, with the type strain being NIBRBAC000500504T (= KCTC 72278T = JCM 33432T).

INFLUENCE OF BIOFUMIGATION WITH MUSTARD OR CANOLA SEED MEAL IN CONTROLLING SOIL-BORNE PATHOGENIC FUNGI OF CHICKPEA

Damping-off and root-rot are important diseases attacking chickpea (Cicer arietinum L.) in Egypt. The effect of biofumigation, using mustard (Brassica juncea) and canola (Brassica napus) seed meals were evaluated to control damping-off and root-rot diseases of chickpea in vitro and in vivo (under greenhouse and field conditions trials) conducted in Sers-Ellian Agricultural Research Station, Menoufia governorate, Egypt, in 2016/2017 and 2017/2018. Both mustard and canola seed meals significantly decreased the linear growth of the tested pathogenic fungi, i.e., Fusarium oxysporum, Sclerotinia sclerotiorum and Rhizoctonia solani, this decrease was more important with the increasing of concentration when compared with the control. The fungicidal effect of mustard and canola seed meals against the tested fungi was demonstrated under greenhouse and field conditions. Obtained results indicated that mustard and canola seed meals significantly reduced the percentages of damping-off severity furthermore improved growth parameters, i.e., plant height, pods number per plant and 100-seed weight. Mustard seed meal recorded the highest values of reduction in this respect as well as, significantly increased nodulation statusof rhizobium (Mesorhizobium ciceri) i.e., number of nodules, nodules fresh and dry weights on chickpea roots in pots and field experiments. Mustard seed meal was superior. It could be concluded, that applying of such biofumigation procedure in the control of chickpea damping-off and root rot diseases on the field scale may offer a practical complement environmentally safe measure to control soil-borne pathogens, and may be combined in an integrated diseases management regime.

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