Pollen Sterility Research Articles

Changeability of quantitative and quality signs of pollen of Robinia pseudoacacia L. is in the conditions of megalopolis

The work is aimed at spreading the practice of bioindication, in particular palynoindication of atmospheric air quality in the surface layer. It is possible to continue monitoring the state of the environment in Ukraine under the conditions of the destructive impact of military operations only with the use of methodologically and economically accessible approaches. The obtained results provide an opportunity to make scientifically based conclusions about the state of the environment and recommendations for zoning territories according to environmental risks for the population. Assessment of the state of atmospheric air in the surface layer is important for determining the potential consequences for the ecosystem and for assessing the risk to public health. We believe that the most informative are the results of the study of plants of the shrub layer. Their generative part is exposed to the long-term effects of the main components of air pollution in the zone of maximum impact on the respiratory system of people. Cytogenetic testing was carried out on Robinia pseudoacacia plants, which belong to the group of sensitive phytoindicator species. Monitoring was carried out during 2020–2021 at 7 locations of park, forest-park ecosystems and street landscaping in four administrative districts of Kyiv. The analysis of weather and climate conditions, the differences of the studied territories in terms of the level of atmospheric air pollution, the level of anthropogenic load, the intensity of transport connections, as well as the provision of green spaces as the main factor in reducing the impact of the urban environment on the state of life and health of the population is given. It was noted that the pollen sterility index reflects the influence of non-optimal factors of the growing environment on the reproductive potential of R. pseudoacacia. The variability of the morphometric characteristics of dry grains according to the shape index is also a fairly informative indicator of its quality. In particular, a tendency to decrease in the equatorial diameter and a further prolonged decrease in the length of the polar axis during the flowering phase of plants was observed. A significant increase in the proportion of degenerated and hypertrophied grains of R. pseudoacacia was noted in areas with significant influence of a complex of exogenous factors and year conditions. Intensive inhibition of the microsporogenesis process was noted in plants in areas with active traffic. Minimal violations were observed in plants from large park plantations. A certain improvement in the state of the atmospheric air during the lockdown period also contributed to a decrease in the number of morphologically abnormal grains. The results of cytotesting of the sensitivity of R. pseudoacacia pollen to the influence of factors of the growing environment can serve as an important component of the assessment of the quality of the environment and zoning of the territories of the metropolis.

The effects of heat stress on male reproduction and tillering in Sorghum bicolor

AbstractDue to global climate change, heat stress is increasingly harming the growth, development, overall biomass, and grain yield of numerous crops. Heat stress impairs pollen development and thus reduces seed set in Sorghum bicolor (L.) Moench; however, the effects of heat stress on anther development at specific stages and tiller formation remain incompletely understood. Here we report that exposure to heat stress [42°C/32°C (day/night)] at pollen mother cell (PMC) and booting stages profoundly disrupts tapetum and pollen development, resulting in a significant decrease in grain yield in sorghum. Sorghum plants subjected to 9 days or less of heat stress at the PMC stage exhibited normal pollen viability, but 12 days of heat stress caused almost complete loss of grain yield and the formation of nonviable pollen grains. Similarly, sorghum plants that were heat‐stressed for 3 days at the booting stage produced few seeds. Further analysis revealed that aberrant tapetum and pollen development contributed to the sterility of pollen in these heat‐stressed plants. Notably, in addition to inhibiting plant height, a 12‐day heat stress at the PMC stage promoted the formation of basal tillers, whereas a 3‐day heat stress at the booting stage stimulated the formation of apical tillers, which helped salvage seed yield under heat stress conditions. Moreover, the application of exogenous auxin promoted the formation of apical tillers and leaf numbers per apical tiller. Collectively, our findings suggest that sorghum is susceptible to heat stress during both early and late anther development, and auxin might be involved in governing the formation of apical tillers.

Breeding Cultivars for Resistance to the African Sweetpotato Weevils, Cylas puncticollis and Cylas brunneus, in Uganda: A Review of the Current Progress.

In sub-Saharan Africa, sweetpotato weevils are the major pests of cultivated sweetpotato, causing estimated losses of between 60% and 100%, primarily during dry spells. The predominantly cryptic feeding behavior of Cylas spp. within their roots makes their control difficult, thus, host plant resistance is one of the most promising lines of protection against these pests. However, limited progress has been made in cultivar breeding for weevil resistance, partly due to the complex hexaploid genome of sweetpotato, which complicates conventional breeding, in addition to the limited number of genotypes with significant levels of resistance for use as sources of resistance. Pollen sterility, cross incompatibility, and poor seed set and germination in sweetpotato are also common challenges in improving weevil resistance. The accurate phenotyping of sweetpotato weevil resistance to enhance the efficiency of selection has been equally difficult. Genomics-assisted breeding, though in its infancy stages in sweetpotato, has a potential application in overcoming some of these barriers. However, it will require the development of more genomic infrastructure, particularly single-nucleotide polymorphism markers (SNPs) and robust next-generation sequencing platforms, together with relevant statistical procedures for analyses. With the recent advances in genomics, we anticipate that genomic breeding for sweetpotato weevil resistance will be expedited in the coming years. This review sheds light on Uganda's efforts, to date, to breed against the Cylas puncticollis (Boheman) and Cylas brunneus (Fabricius) species of African sweetpotato weevil.

Redundant function of the Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K4-6 is essential for pollen germination.

Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is a key enzyme producing the signaling lipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] in eukaryotes. Although PIP5K genes are reported to be involved in pollen tube germination and growth, the essential roles of PIP5K in these processes remain unclear. Here, we performed a comprehensive genetic analysis of the Arabidopsis thaliana PIP5K4, PIP5K5, and PIP5K6 genes and revealed that their redundant function is essential for pollen germination. Pollen with the pip5k4pip5k5pip5k6 triple mutation was sterile, while pollen germination efficiency and pollen tube growth were reduced in the pip5k6 single mutant and further reduced in the pip5k4pip5k6 and pip5k5pip5k6 double mutants. YFP-fusion proteins, PIP5K4-YFP, PIP5K5-YFP, and PIP5K6-YFP, which could rescue the sterility of the triple mutant pollen, preferentially localized to the tricolpate aperture area and the future germination site on the plasma membrane prior to germination. Triple mutant pollen grains under the germination condition, in which spatiotemporal localization of the PtdIns(4,5)P2 fluorescent marker protein 2xmCHERRY-2xPHPLC as seen in the wild type was abolished, exhibited swelling and rupture of the pollen wall, but neither the conspicuous protruding site nor site-specific deposition of cell wall materials for germination. These data indicate that PIP5K4-6 and their product PtdIns(4,5)P2 are essential for pollen germination, possibly through the establishment of the germination polarity in a pollen grain.

Biomonitoring of the environment of the Arctic urbanized area using the pollen of Sorbus gorodkovii Pojark

This article investigates the content of heavy metals (Cu, Ni, V, Cd, Zn) in the reproductive organs of the Gorodkov’s rowan (Sorbus gorodkovii Pojark.) growing in the impact zone of environmentally hazardous facilities in Murmansk (CHP plants, waste incineration plant and trade sea port). The samples most contaminated by heavy metals were registered in the vicinity of the incineration plant. High concentrations of vanadium (4,2–4,8 mg/kg) and Cu, Ni, Cd, and Zn exceeding the limits of MPC are revealed in the impact zone of CHP plants operating on fuel oil. Biomonitoring of the viability of S. gorodkovii pollen showed that in all samples, the content of fertile pollen grains was reduced compared to that in the control. At the test sites of the Central and South CHP plants, the proportion of fertile pollen was 35–41 % (compared to 72 % in the control sample). The induced sterility was more than two times higher than the spontaneous sterility. High concentrations of vanadium and other toxic metals in emissions of Heating Plants have a gametocidal effect on the male gametophyte of S. gorodkovii. Groups of fertile and sterile pollen grains were selected according to their size: dwarf, normal, or hypertrophied. In the vicinity of the CHP plants, the proportion of fertile pollen of normal size decreased (62–69 %), whereas the content of dwarf (16–18 %) and hypertrophic pollen (17.4–22.7 %) increased. Sterile pollen grains were mostly dwarf (63–70 %). The results of biomonitoring indicated that CHP plants polluted the urban environment with vanadium and other toxic metals, which caused sterilization of S. gorodkovii male gametes. To improve the ecological situation in Murmansk, it is necessary to switch the thermal stations for the use of natural gas.

Cytogenetic Study and Pollen Viability of Phalaenopsis Queen Beer 'Mantefon'.

Intergeneric and interspecific hybridization has been employed for the breeding of Phalaenopsis to transfer desirable traits between species, producing novel phenotypes with improved size, color, form, and flower-bearing ability. These characteristics are often enhanced; however, many of these hybrids are triploids and have reduced or complete sterility, for example, Phalaenopsis Queen Beer 'Mantefon', an important novelty-type cultivar in Asia, particularly in China, Japan, and Republic of Korea. Despite the increasing demand for the crop for ornamental purposes, little is known about its cytogenetics, which is essential for breeding and, consequently, crop improvement. In this study, karyotyping using fluorescence in situ hybridization, meiotic chromosome behavior analysis, pollen staining, and in vitro viability germination tests were performed to understand the cause of hybrid sterility and pollen abnormality in Phalaenopsis Queen Beer 'Mantefon' from a cytogenetic perspective. Viability tests revealed pollen infertility at all flower developmental stages, confirmed by the absence of pollen tube growth. Aberrant chromosomal behavior was observed in pollen mother cells (PMCs), frequently forming univalents, chromosomal bridges, and laggards during the entire meiotic process. PMCs were also divided irregularly into sporads with varying numbers of micronuclei, which may be responsible for pollen sterility in this cultivar. Altogether, the cytogenetic analyses provided insights into the pollen development of Phalaenopsis Queen Beer 'Mantefon' and the conceivable causes of its infertility.

Genotype-mutagenic interaction in the cytogenetic variability of winter wheat for a new ecogenetic factor

The study of cytogenetic parameters of the activity of new mutagenic factors aims to reliably establish the possibilities of these factors in terms of variability depending on the subject of mutagenic action, the optimal use of certain factor sizes, the combination of the selected protocol with optimization of the yield of mutant forms in the future. Seeds of eight varieties of winter wheat (Balaton, Borovytsia, Zeleny Gai, Zoloto Ukrainy, Kalancha, Niva Odeska, Polyanka, Pochayna) were treated by SA (sodium azide) at concentrations of 0.010%, 0.025%, 0.05%, 0.10%. They were soaked in water solution for 24 hours. Cytogenetic activity was evaluated by pollen sterility, evaluation of general rates and indicators of spectra of chromosomal abnormalities at medium phases of cell mitosis according to wheat variety and chemical agent concentrations. As a result of the study, the key importance of the genotype-mutagenic interaction was demonstrated within the limits of variability of the main indicators of the frequency and spectrum of chromosomal aberrations. It has been established that in the future it will be more optimal to use two varieties whose genotype-mutagenic specificity indicators are significantly higher and one should expect a more significant yield of promising mutant forms from them in the future, especially in combination with SA concentrations in the range of 0.025% and 0.05%. It is demonstrated that the main parameters that reflect genetically determined possibilities in susceptibility to the ecogenetic factor are pollen fertility, the overall frequency of chromosome aberrations, and the number of induced fragments. The use of other parameters displays the trend only partially or does not display it at all, as is the case with the use of rarer types of chromosomal rearrangements. The least promising forms have also been identified for use as starting material in treatments with this substance. It is demonstrated that, in general, this agent is characterized by the same patterns in the induction of cytogenetic activity as for other chemical supermutagens, with some variations depending on the starting material. In the future, it is planned to link the obtained data with the frequency and quality of the resulting hereditary changes, primarily complex biochemical and physiological ones, in order to improve the quality of plant products and various types of plant tolerance to adverse environmental conditions.

Role of Micronutrients Towards Crop Productivity under Biotic and Abiotic Stresses: A Review

In recent scenarios, the world’s food system is highly insecure and become a great challenge to the rapidly growing civilization. Agriculture is intricately tied to food security and life sustainability on earth. The arising climatic alteration forces plants to compete for nutrients from the soil. Crop yielding and their nutritional quality are highly influenced by environmental factors (biotic and abiotic stress), agronomic factors, pests and nutrient availability in the soil. These are the nanoparticle that monitors the elements in soil by sharing some signals. Micronutrients help to maximize plant growth and protect plants from diseases and pathogens. But the alteration of the environmental condition is highly responsible for nutrient limitation and growth inhibition. 35% of the world’s agricultural lands are decreasing their soil fertility, which leads to nutrient deficiency in plants. These insufficient nutrients of crops lower the yield and nutritional quality of food and affected human health. In the reproductive stage of plant growth, environmental stress is highly responsible for flower drop, pollen tube deformation, ovule abortion, pollen sterility and yield losses. A sufficient quantity of micronutrients can help to reduce the biotic and abiotic stress in agricultural crops. The current review gives a brief knowledge to understand the current features of micronutrients in the agricultural crop which focus on the mechanism, absorption activity, toxicity and deficiency of micronutrients in plants and how it secures our food system by increasing the yield and nutritional quality.

Creation and a breeding-genetic study of pollinator lines - sterility fixers and their CMS-analogues in fodder beet breeding for heterosis

Purpose. To create pollinator lines - sterility fixers and their cytoplasmic male sterility (CMS)-analogues and to study their breeding and genetic features for the development of parental components of CMS-based one-sprout fodder beet hybrids.
 Materials and Methods. The study was carried out at the Tobacco Research Station of the National Scientific Center "IA NAAS" (Cherkaska Oblast, Uman) in 2013–2021. Four diploid one-sprout fodder beet populations of hybrid origin were taken as the starting material. Fodder beet lines were created by inbreeding. Analyzing crossings were carried out under paired coarse calico bags. Breeding accessions were tested in accordance with a method developed by scientists of the Institute of Bioenergy Crops and Sugar Beet of NAAS.
 Results and Discussion. The results indicate a fairly high frequency of pollinators - sterility fixers among the one-sprout fodder beet hybrids bred in Uman. The mean across all the initial accessions was 7.5%. One-sprout hybrids KT-7105 2хmm and KZ-1507 2хmm demonstrated the highest incidence Owen type pollinators - sterility fixers. A high level of pollen sterility was intrinsic to the CMS analogues of the O-type lines derived from the initial accessions IM-3319 2хmm and KZ-1507 2хmm (99.1% and 97.0%, respectively). The highest percentage of one-sprout seeds was recorded for the CMS analogues of the O-type lines derived from hybrid accessions KZ-1507 2хmm and KT-7105 2хmm. Fifteen best O-type lines have been selected for further breeding to obtain parental components of CMS-based experimental hybrids.
 Analysis showed that the beetroot yields of the majority of the CMS fodder beet lines were lower than that of the check variety. CMS IM-3319/16, CMS IM-3319/34 and CMS IM-3319/49 were the only lines that yielded at the level of the check variety (80.9–83.6 t/ha), which is attributed primarily to their genetic origin. As to the dry matter content in beetroots, only lines CMS ST-4514/27 and CMS ST-4514/39 significantly exceeded the check variety; the values of the others were similar to that of the check variety. In terms of the dry matter output, except for CMS KT-7105/7, CMS IM-3319/34 and CMS IM-3319/49, most lines were inferior to the check variety.
 Conclusions. We found that the portion of pollinators - CMS fixers in one-sprout populations of fodder beets of different genetic origins was 3.7–11.3%. Fifteen combinable O-type lines with pollen sterility fixing of 96.2–100% and percentage of one-sprout seeds of 96.4–99.3% have been created. Their CMS analogues have been obtained. The created breeding accessions are a valuable starting material for the selection of parental components and generation of highly productive CMS-based one-sprout fodder beet hybrids

The Effects of Growth Modification on Pollen Development in Spring Barley (Hordeum vulgare L.) Genotypes with Contrasting Drought Tolerance

Drought stress inducing pollen sterility can reduce crop yield worldwide. The regulatory crosstalk associated with the effects of drought on pollen formation at the cellular level has not been explored in detail so far. In this study, we performed morphological and cytoembryological analysis of anther perturbations and examined pollen development in two spring barley genotypes that differ in earliness and drought tolerance. The Syrian breeding line CamB (drought-tolerant) and the European cultivar Lubuski (drought-sensitive) were used as experimental materials to analyze the drought-induced changes in yield performance, chlorophyll fluorescence kinetics, the pollen grain micromorphology and ultrastructure during critical stages of plant development. In addition, fluctuations in HvGAMYB expression were studied, as this transcription factor is closely associated with the development of the anther. In the experiments, the studied plants were affected by drought, as was confirmed by the analyses of yield performance and chlorophyll fluorescence kinetics. However, contrary to our expectations, the pollen development of plants grown under specific conditions was not severely affected. The results also suggest that growth modification, as well as the perturbation in light distribution, can affect the HvGAMYB expression. This study demonstrated that the duration of the vegetation period can influence plant drought responses and, as a consequence, the processes associated with pollen development as every growth modification changes the dynamics of drought effects as well as the duration of plant exposition to drought.

Anatomy and Comparative Transcriptome Reveal the Mechanism of Male Sterility in Salvia miltiorrhiza.

Salvia miltiorrhiza Bunge is an important traditional herb. Salvia miltiorrhiza is distributed in the Sichuan province of China (here called SC). Under natural conditions, it does not bear seeds and its sterility mechanism is still unclear. Through artificial cross, there was defective pistil and partial pollen abortion in these plants. Electron microscopy results showed that the defective pollen wall was caused by delayed degradation of the tapetum. Due to the lack of starch and organelle, the abortive pollen grains showed shrinkage. RNA-seq was performed to explore the molecular mechanisms of pollen abortion. KEGG enrichment analysis suggested that the pathways of phytohormone, starch, lipid, pectin, and phenylpropanoid affected the fertility of S. miltiorrhiza. Moreover, some differentially expressed genes involved in starch synthesis and plant hormone signaling were identified. These results contribute to the molecular mechanism of pollen sterility and provide a more theoretical foundation for molecular-assisted breeding.

Tomato Biodiversity and Drought Tolerance: A Multilevel Review.

Ongoing global climate change suggests that crops will be exposed to environmental stresses that may affect their productivity, leading to possible global food shortages. Among these stresses, drought is the most important contributor to yield loss in global agriculture. Drought stress negatively affects various physiological, genetic, biochemical, and morphological characteristics of plants. Drought also causes pollen sterility and affects flower development, resulting in reduced seed production and fruit quality. Tomato (Solanum lycopersicum L.) is one of the most economically important crops in different parts of the world, including the Mediterranean region, and it is known that drought limits crop productivity, with economic consequences. Many different tomato cultivars are currently cultivated, and they differ in terms of genetic, biochemical, and physiological traits; as such, they represent a reservoir of potential candidates for coping with drought stress. This review aims to summarize the contribution of specific physio-molecular traits to drought tolerance and how they vary among tomato cultivars. At the genetic and proteomic level, genes encoding osmotins, dehydrins, aquaporins, and MAP kinases seem to improve the drought tolerance of tomato varieties. Genes encoding ROS-scavenging enzymes and chaperone proteins are also critical. In addition, proteins involved in sucrose and CO2 metabolism may increase tolerance. At the physiological level, plants improve drought tolerance by adjusting photosynthesis, modulating ABA, and pigment levels, and altering sugar metabolism. As a result, we underline that drought tolerance depends on the interaction of several mechanisms operating at different levels. Therefore, the selection of drought-tolerant cultivars must consider all these characteristics. In addition, we underline that cultivars may exhibit distinct, albeit overlapping, multilevel responses that allow differentiation of individual cultivars. Consequently, this review highlights the importance of tomato biodiversity for an efficient response to drought and for preserving fruit quality levels.

Evaluation of Cytoplasmic Male Sterile Lines and Restorer Lines in Moricandia System for Heterosis Breeding in Indian Mustard [Brassica juncea (L.) Czern & Coss.

This study was undertaken with the objectives of Cytoplasmic Male Sterility (CMS) assessment and study of pollen fertility restoration using five Mori based Cytoplasmic Male Sterile lines viz., Mori ‘A’ SKM 109, Mori ‘A’ SKM 125, Mori ‘A’ SKM 201, Mori ‘A’ SKM 219, Mori ‘A’ SKM 303 and eight diverse Mori based fertility restorer lines viz., Mori ‘R’ GM 2, Mori ‘R’ GM 3, Mori ‘R’ SKM 9033, Mori ‘R’ SKM 301, Mori ‘R’ Pusa Bahar, Mori ‘R’ Vardan, Mori ‘R’ Bio 902, Mori ‘R’ 1-14 to identify good fertility restorer line and stain ability of pollen grains of sterile and fertile lines to Moricandia arvensis, cytoplasmic background of converted cytoplasmic male sterile lines of Indian Mustard [Brassica juncea (L.) Czern & Coss.] by repeated backcrossing at the Main Castor-Mustard Research station, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar-385506 Banaskantha. The pollen stain ability, plant fertility status and percentage siliquae set per plant was recorded for the morphological characterization and to confirm stability of true Cytoplasmic Male Sterile (CMS) line. The experimental material comprised of fifty-four genotypes consisting of five diverse CMS lines and eight Fertility Restorer lines were crossed in line X tester mating design and resultant forty hybrids along with their thirteen parents and standard check variety (Kranti) were evaluated in randomized block experimental design. The morphological characters were studied viz., pollen fertility, Number of siliquae set per plant, per cent siliquae set per plant in field as well as laboratory tests were conducted with 2 % Aceto-carmine to confirm pollen stain ability and purity of CMS (A-lines) for male sterility and pollen fertility restorability of R-lines. There were visual differences observed for the parents (male sterile lines and fertility restorer lines), all the F1 crosses and standard check parent for pollen fertility. The male sterile lines exhibited (100%) pollen sterility and the pollen fertility restorer lines varied from 80.05 % (Mori ‘R’ Pusa Bahar) to 97.97 %(Mori ‘R’ SKM 9033).

Multiple-statistical genome-wide association analysis and genomic prediction of fruit aroma and agronomic traits in peaches.

'Chinese Cling' is an important founder in peach breeding history due to the pleasant flavor. Genome-wide association studies (GWAS) combined with genomic selection are promising tools in fruit tree breeding, as there is a considerable time lapse between crossing and release of a cultivar. In this study, 242 peaches from Shanghai germplasm were genotyped with 145 456 single-nucleotide polymorphisms (SNPs). The six agronomic traits of fruit flesh color, fruit shape, fruit hairiness, flower type, pollen sterility, and soluble solids content, along with 14 key volatile odor compounds (VOCs), were recorded for multiple-statistical GWAS. Except the reported candidate genes, six novel genes were identified as associated with these traits. Thirty-nine significant SNPs were associated with eight VOCs. The putative candidate genes were confirmed for VOCs by RNA-seq, including three genes in the biosynthesis pathway found to be associated with linalool, soluble solids content, and cis-3-hexenyl acetate. Multiple-trait genomic prediction enhanced the predictive ability for γ-decalactone to 0.7415 compared with the single-trait model value of 0.1017. One PTS1-SSR marker was designed to predict the linalool content, and the favorable genotype 187/187 was confirmed, mainly existing in the 'Shanghai Shuimi' landrace. Overall, our findings will be helpful in determining peach accessions with the ideal phenotype and show the potential of multiple-trait genomic prediction to improve accuracy for highly correlated genetic traits. The diagnostic marker will be valuable for the breeder to bridge the gap between quantitative trait loci and marker-assisted selection for developing strong-aroma cultivars.

Chemical emasculation in cowpea (Vigna unguiculata (L.) Walp.) and dicotyledonous model species using trifluoromethanesulfonamide (TFMSA)

Hybridization plays an indispensable role in creating the diversity associated with plant evolution and genetic improvement of crops. Production of hybrids requires control of pollination and avoidance of self-pollination for species that are predominantly autogamous. Hand emasculation, male sterility genes or male gametocides have been used in several plant species to induce pollen sterility. However, in cowpea (Vigna unguiculata (L.) Walp), a self-pollinated cleistogamous dryland crop, only hand emasculation is used, but it is tedious and time-consuming. In this study, male sterility was effectively induced in cowpea and two dicotyledonous model species (Arabidopsis thaliana (L.) Heynh. and Nicotiana benthamiana Domin) using trifluoromethanesulfonamide (TFMSA). Pollen viability assays using Alexander staining showed that 30 ml of 1000 mg/l TFMSA with two-time treatments of one-week interval at the early stage of the reproductive phase under field or greenhouse conditions induced 99% pollen sterility in cowpea. TFMSA treatment induced non-functional pollen in diploid A. thaliana at two-time treatment of 10 ml of 125–250 mg/l per plant and N. benthamiana at two-time treatment of 10 ml of 250–1000 mg/l per plant. TFMSA-treated cowpea plants produced hybrid seeds when used as the female parent in crosses with non-treated plants used as male parents, suggesting that TFMSA had no effect on female functionality in cowpea. The ease of TFMSA treatment and its effectiveness to induce pollen sterility in a wide range of cowpea genotypes, and in the two model plant species tested in this study, may expand the scope of techniques for rapid pollination control in self-pollinated species, with potential applications in plant breeding and plant reproduction science.

Assessment of Cytomorphological Differences in Sorghum Fertility Restoration

Sorghum (Sorghum bicolor L. Moench) is ranked fifth as a cereal crop after maize, rice, wheat, and barley based on global cultivation area. However, heat and drought stresses cause improper fertility restoration and inefficient pollination, severely affecting sorghum productivity. The discovery of cytoplasmic male sterility (CMS) is a milestone for commercializing hybrids. This study assessed the pollen fertility and in vitro pollen germination percentage of male and female lines and F1 hybrids of sorghum using two years of pooled data with multivariate analysis. The principal component analysis (PCA) of female and male lines showed that PC1 represented 82.8% of the variation, whereas PCA of hybrids revealed a significant genetic divergence of 97.1%. Agglomerative hierarchical clustering marked that cluster II genotypes have a high pollen fertility contribution, which can generate superior and high-yielding hybrids. Three male-sterile lines exhibited 100% pollen sterility, with morphological attributes, viz., pinpointed, flattened, low anther extrusion, and starch-digested pollens. Pollen fertility restoration behavior revealed that nine hybrids were fully fertile, eighteen were partially fertile, and three were completely sterile amongst thirty hybrids. The findings of this study will facilitate the identification of potential restorers for the exploitation of high-yielding hybrids in sorghum breeding programs.

Palyno-taxonomic approach through light and scanning electron microscopy for the identification of herbaceous Asteraceae species from Sikaram Mountain Pak-Afghan border.

Due to the diverse and rich taxa, Asteraceae needs to explore from the untouched area. In this study, the pollen study was intended to assess the taxonomic value for Asteraceous taxa growing on the Sikaram Mountain Pak-Afghan border. Both microscopic techniques (LM and SEM) play a significant role in the identification and classification of herbaceous species of Asteraceae for their taxonomic and systematic implication. Pollen was observed and measured for the 15 species of Asteraceae. For investigated taxa 15 pollen characters with size, shape, polar view, pollen type, aperture orientation, and exine sculpturing in the eurypalynous pollen. Consequently, the pollen grains are usually Tricolporate, triangular to circular in polar view, while, the shape of pollen varies from subulate, oblate, and prolate along with prolate to spheroidal whereas, sculpturing also varies from Scabrate to micro reticulate, echino-perforate, Scabrate to echinate, echinate to granulate and echinate were observed. Similarly, among the quantitative data minimum values of polar and equatorial were 15.8 ± 0.74 μm in Filago pyramidata and 17.85 ± 0.39 μm in Heteropappus altaicus was measured respectively, while; the length of the spine with the least value of 2.45 ± 0.31 μm in Hertia intermedia and highest with 7.55 ± 0.31 μm was observed in Cirsium wallichii. The Exine thickness is a minimum of 1.70 ± 0.35 μm in Launaea nudicaulis and a maximum of 5.65 ± 3.59 μm in Cirssium vulgare. In addition, the highest pollen fertility (87%) in Centaurea iberica while the highest pollen sterility (32%) was recorded in Cirsium verutum. Furthermore, clustering via UPGMA, PCA, and PCoA analysis was performed for the separation of closely related taxa. It is concluded from this research work that palynological study has a crucial role in taxonomic, pure, and applied sciences. This study can be further authenticated and improved by a Phylogenetic study based on chloroplast DNA analysis & whole genome sequencing. RESEARCH HIGHLIGHTS: Pollen ultrastructure among 15 Asteraceous taxa. Micromorphological attributes measured via LM and SEM. Exine sculpture elements patterns provide accurate identification. Taxonomic keys were developed for its systematics implications.

Desert endophytic fungi improve reproductive, morphological, biochemical, yield and fruit quality characteristics of tomato under drought stress

PurposeCrops are increasingly affected by drought; hence, the current study explored the potential role of three desert endophytic fungi, Aspergillus fumigatus, Aspergillus terreus and Talaromyces variabilis, in conferring drought tolerance in tomato plants.Design/methodology/approachPreserved endophytic fungi from a Rhazya stricta desert plant were adopted to obtain the required fungal treatment; tomatoes received fungal treatments directly in plastic trays and subsequently in pots. Drought was applied using 15% of PEG-6000 at two stages: flowering and fruiting. The following parameters were measured: pollen sterility, growth characteristics, morphological analysis and biochemical analysis, including proline, gibberellic acid (GA3) and chlorophyll measurements; thus, the data were analyzed statistically using SPSS software.FindingsAll applied endophytes significantly promoted pollen viability and tomato yield under stressed and nonstressed conditions. Interestingly, these endophytes significantly enhanced the number of trichomes under drought stress and promoted tomato fruit quality. The colonized tomato plants accumulated a high proline level under drought stress but lower than un-inoculated stressed plants. Also, a significant rise in growth characteristics was observed by A. fumigatus and A. terreus under normal conditions. Moreover, both raised GA3 levels under drought-stressed and nonstressed conditions. Also these two endophytes enhanced chlorophyll and carotenoid contents under drought stress. Fruit characteristics were enhanced by nonstressed T. variabilis and stressed A. fumigatus.Originality/valueThe present endophytic fungi provide impressive benefits to their host in normal and drought-stressed conditions. Consequently, they represent valuable sources as sustainable and environmentally friendly alternatives to mitigate drought stress.

Status of the biopesticide market and prospects for new bioherbicides.

Biopesticides (commonly called Biocontrol or more recently bioprotection) have been experiencing double digit growth and now comprise about 10% of the global pesticide market driven by increased return on investment, restrictions on chemical pesticides, and pesticide resistance and residue management. However, despite the large need for new herbicides due to widespread and increasing resistance to herbicides with almost most of the chemical modes of action, bioherbicides are an insignificant percentage of the total. The technical difficulty in finding bioherbicides that can compete with the spectrum and price of chemical herbicides has left agriculture with a paucity of new bioherbicides. Billions of dollars of investment capital is being invested in new, innovative startups, but only a small number focus on bioherbicide discovery and development, due to the perceived higher risk than plant biotech, biostimulants, bionutrients and other categories of biopesticides. However, the exciting new technologies that these startups are developing such as RNAi, sterile pollen, and systemic metabolites have potential to impact the market in ten years or less. This article is protected by copyright. All rights reserved.

Abrin inactivating mitochondrial ribosome induced anther abortion in cotton CMS line LD6A by damaging mitochondrial membrane structure

Cytoplasmic male sterile (CMS) system has extensively been exploited for hybrid vigor in plant breeding programs. However, its application in many crops is limited due to poor understanding of molecular mechanism of fertility restoration. Using advanced analytical approaches, we aimed to elucidate the molecular pathways, regulating CMS induction and fertility restoration in cotton. Reproductive structures of a novel CMS (LD6A) and its maintainer (LD6B) lines were analyzed for physiological and proteomic changes during the development process. Transmission electron micrographs of anther tapetum showed a relatively indistinct inner ridge of CMS than of LD6B mitochondria at tetrad stage. Furthermore, at pollen mother cell and tetrad stages, CMS anthers accumulated a significantly higher reactive oxygen species than the maintainer line. At the protein level, CMS anthers induced significantly higher Abrin (XP_016705148.2), lower tricarboxylic acid cycle enzyme (malate dehydrogenase, malic enzyme, isocitrate dehydrogenase), and histone acetyltransferase expression than its maintainer line. Suggesting that abnormal sequence of mitochondrial ribosome gene rps4 and rpl10 and high expression of ribosome-inactivating protein Abrin in CMS line damaged mitochondrial membrane. This inhibited energy supply from the non-degraded tapetum, and consequently induced pollen sterility in LD6A. These data provide new insights into CMS mechanism in cotton crops that can be used for developing new CMS germplasm resources.