Cytoplasmic Effects Research Articles

Transcriptomic Communication between Nucleus and Mitochondria during the Browning Process of Lentinula edodes.

To explore the reason for cytoplasmic replacement's significant effect on browning, transcriptomic data of nuclear (N) and mitochondrial (M) mRNAs and long noncoding RNAs (lncRNAs) in L808 and two cytoplasmic hybrids (cybrids) (L808-A2 and L808-B) of Lentinula edodes at three different culturing times (80, 100, and 120 days) were obtained. The results showed that the expression of N and M genes and lncRNAs changed with the culture time and cytoplasmic source. Cytoplasmic replacement significantly affected some M and N genes related to the internal mechanism and external morphological characteristics of L. edodes browning. The internal browning mechanism should be the nicotinamide adenine dinucleotide phosphate (NADPH)-mediated antioxidant machinery to protect mycelia against oxidative stress induced by the generation of reactive oxygen species under light irradiation. External morphological characteristics were the changing features of brown films by melanin (an antioxidant) aggregation on the surface of the mycelia of the bag or log. Especially, some genes were related to the remodeling of the plasma membrane, extracellular enzymes of celluloses and hemicellulases, small molecules, and NADPH metabolic processes. Additionally, communication between the nucleus and mitochondria mediated by M-rps3 was reported for the first time, and it is mainly appreciated in M structural assembly, functional implementation, and cooperation with other organelles.

Insights into cellular crosstalk regulating cytoplasmic male sterility and fertility restoration.

Cytoplasmic male sterility has been a popular genetic tool in development of hybrids. The molecular mechanism behind maternal sterility varies from crop to crop. An understanding of underlying mechanism can help in development of new functional CMS gene in crops which lack effective and stable CMS systems. In crops where seed or fruit is the commercial product, fertility must be recovered in F1 hybrids so that higher yield gains can be realized. This necessitates the presence of fertility restorer gene (Rf) in nucleus of male parent to overcome the effect of sterile cytoplasm. Fertility restoring genes have been identified in crops like wheat, maize, sunflower, rice, pepper, sugar beet, pigeon pea etc. But in crops like eggplant, bell pepper, barley etc. unstable fertility restorers hamper the use of Cytoplasmic genic male sterility (CGMS) system. Stability of CGMS system is influenced by environment, genetic background or interaction of these factors. This review thus aims to understand the genetic mechanisms controlling mitochondrial-nuclear interactions required to design strong and stable restorers without any pleiotropic effects in F1 hybrids.

The timing of pronuclear transfer critically affects the developmental competence and quality of embryos.

Pronuclear transfer has been successfully used in human-assisted reproduction to suppress the adverse effects of a defective oocyte cytoplasm or to bypass an idiopathic developmental arrest. However, the effects of the initial parental genome remodelling in a defective cytoplasm on the subsequent development after pronucleus transfer have not been systematically studied. By performing pronuclear transfer in pre-replication and post-replication mouse embryos, we show that the timing of the procedure plays a critical role. Although apparently morphologically normal blastocysts were obtained in both pre- and post-replication pronuclear transfer groups, post-replication pronuclear transfer led to a decrease in developmental competence and profound changes in embryonic gene expression. By inhibiting the replication in the abnormal cytoplasm before pronuclear transfer into a healthy cytoplasm, the developmental potential of embryos could be largely restored. This shows that the conditions under which the first embryonic replication occurs strongly influence developmental potential. Although pronuclear transfer is the method of choice for mitigating the impact of a faulty oocyte cytoplasm on early development, our results show that the timing of this intervention should be restricted to the pre-replication phase.

Diallel analysis, maternal effect and heritability in groundnut for yield components and oil content

BackgroundGroundnut is one of the world's major food and oil crops. Being sources of nutrition and vegetable oil, rich in affordable and digestible protein, it is a strategic crop in Burkina Faso for food security, nutrition, and cash income. Understanding the nature of gene effect and genetic variation affecting yield and yield component traits will contribute to designing appropriate breeding methods for groundnut improvement and increase selection efficiency in Burkina Faso. MethodsIn 2018, a total of 30 F2 progenies were generated through a 6 x 6 full diallel mating using six different and contrasting varieties. In 2019, parents and progenies were evaluated in a lattice square design in 3 replications at ICRISAT-Mali experimental field to assess the general combining ability (GCA) and specific combining ability (SCA) effects, the inheritance and the maternal and reciprocal effects for yield component traits (YCT) and oil content (OC). ResultsSignificant variabilities were observed among the parental genotypes and their F2 progenies for DTH, PSR, HPW, PL, PWD, SL, SWD, and OAC. Mean performance of the six parents were HPW (117.05g), HSW (57.24 g), PYH (1914.76), SYH (1312.73), PL (2.52), PWD (1,19), SL (1.38), SWD (0.83), OC (49.43), OAC (50.43) and LAC (33.61). Parent QH243C presented the highest value for SWD (1.02 cm) and OAC (60.76) while the parent ICGV09195 had the highest value of OC (50.36). Chalimbana presented the highest value of HPW (169.61 g), PL (2.98 cm), PWD (1. 41 cm), and SL (1.57 cm) while CG7 presented the highest value for HSW (75. 14 g), and SYH (1639.28 kg). Both YCT and OC are controlled by additive and non-additive gene effects with a predominance of additive gene action for HSW, SL, and SWD, whereas HPW, PL, PWD, and OAC were found to be more controlled by non-additive gene effects. Maternal effects as well as nuclear and cytoplasmic interaction effects were observed for both YCT and OC indicating that YCT and OC are influenced by a combination of genetic factors from both the maternal parent and the nuclear genome, as well as cytoplasmic factors such as mitochondrial DNA. Broad sense heritability ranged from 3.76 % to 91.56 %, and higher broad sense heritability values were recorded for pod length (91.56 %), hundred pod weight (83.71 %) and pod width (80.95 %). ConclusionThe study yields valuable insights into the inheritance of YCT and OC. The parents, Chalimbana and CG7, showed promise as good combiners for both yield component traits and oil content when used as male parents while TE3, Sh470P and QH243C can be used as female for the oil content and its components (oleic and linoleic content).

Assessment of combining ability for targeted traits in periwinkle (Catharanthus roseus (L.) G. Don) through diallel analysis

Catharanthus roseus (L.) G. Don is a vital summer season perennial semi shrub and multipurpose drought resilient flower crop of the tropical region of the Indian subcontinent. This industrially dominant crop is primarily availed as border, bedding and pot culture in landscaping; and also cultivated for its anti-cancer alkaloid compounds enriched plant parts. Hence, the present study was focused to explore diversity. Six inbred lines of periwinkle were crossed in full-diallel fashion with an objective of identifying superior cross-combinations for high general, specific and reciprocal combining ability. The analysis of variance for combining ability was highly significant for growth and flowering traits indicated existence of both additive and non-additive gene actions. However some traits showed only additive effect due to non-significant general combining ability. The parental lines of Vi-13–2 and Vi-15–2 expressed superior general combining effects for flower yield and considered as good general combiners for crossing programmes. The cross combinations Vi-15–1 × Vi-14–3 and Vi-16 × Vi-15–2 exhibited significantly positive specific combining ability effects for flower yield and considered as good specific direct combiners. High specific direct cross combiners necessitate poor × good, good × good and poor × poor parental combinations and can be contribute additive × dominance, additive × additive, dominance × dominance and epistatic gene interactions. The specific reciprocal cross combiners identified as Vi-14–3 × Vi-29 and Vi-14–3 × Vi-13–2 with superior expression in the reciprocal magnitudes for various traits might be due to cytoplasmic effects. The current investigation is designed to identify the best performing inbred lines for ornamental utilization as well as lines that can be exploited as parents in subsequent crosses.

Genetic Cause of Hybrid Lethality Observed in Reciprocal Interspecific Crosses between Nicotiana simulans and N. tabacum.

Hybrid lethality, a type of postzygotic reproductive isolation, is an obstacle to wide hybridization breeding. Here, we report the hybrid lethality that was observed in crosses between the cultivated tobacco, Nicotiana tabacum (section Nicotiana), and the wild tobacco species, Nicotiana simulans (section Suaveolentes). Reciprocal hybrid seedlings were inviable at 28 °C, and the lethality was characterized by browning of the hypocotyl and roots, suggesting that hybrid lethality is due to the interaction of nuclear genomes derived from each parental species, and not to a cytoplasmic effect. Hybrid lethality was temperature-sensitive and suppressed at 36 °C. However, when hybrid seedlings cultured at 36 °C were transferred to 28 °C, all of them showed hybrid lethality. After crossing between an N. tabacum monosomic line missing one copy of the Q chromosome and N. simulans, hybrid seedlings with or without the Q chromosome were inviable and viable, respectively. These results indicated that gene(s) on the Q chromosome are responsible for hybrid lethality and also suggested that N. simulans has the same allele at the Hybrid Lethality A1 (HLA1) locus responsible for hybrid lethality as other species in the section Suaveolentes. Haplotype analysis around the HLA1 locus suggested that there are at least six and two haplotypes containing Hla1-1 and hla1-2 alleles, respectively, in the section Suaveolentes.

Genetic control of fruit length, external colour and number of fruits per vine in bitter gourd studied using Charantia × Muricata crosses

The present study was undertaken to ascertain the genetic control of external fruit colour, fruit length, and the number of fruits per vine in bitter gourd using reciprocal crosses of Momordica charantia var. muricata and M. charantia var. charantia and to identify suitable lines of M. charantia var. muricata to be used in bitter gourd improvement programmes. Muricata accession collected from Girandurukotte (GK), Sri Lanka, was selected as a suitable accession for crop improvement based on higher gynoecy and consistency of characteristics. Crossing success between Charantia and Muricata varieties was 100 % indicating cross-compatibility between the two types. External fruit colour, fruit length and the number of fruits per vine of bitter gourd were found to be quantitative traits, potentially controlled by many genes, each with a small effect. The number of fruits per vine was found to show cytoplasmic inheritance, as the F1 generation recorded fruit numbers per vine similar to those of Charantia varieties, when Charantia varieties were used as the female parent of the reciprocal crosses made between Charantia and Muricata varieties. However, the suspected cytoplasmic effect was not useful, as it influenced to reduce the number of fruits per vine. In addition, the number of fruits per vine showed several transgressive segregants in both extremes of the F2 populations. In bitter gourd improvement programmes, GK Muricata accession may be used to improve cultivated Charantia varieties with respect to fruit characteristics such as external fruit colour, fruit length and the number of fruits per vine through a breeding program with the directional selection made towards obtaining the desired characters.

Effects of cytoplasm from the related wild species <i>Aegilops mutica</i> on agronomic characters in Japanese bread wheat cultivars

Effects of cytoplasm from the related wild species <i>Aegilops mutica</i> on agronomic characters in Japanese bread wheat cultivars

Genetics of begomovirus resistance in Cucurbita moschata Duchesne: A novel resistant source PVR-1343

Whitefly transmitted begomoviruses are the most destructive virus(es) that causes quantitative and qualitative losses to pumpkin (Cucurbita moschata) crop worldwide. In present study we have molecularly characterized three types of viral infections, which were caused by squash leaf curl China virus (SLCCNV), tomato leaf curl New Delhi virus (ToLCNDV), and their mixed infection (MI-Sq/To). Screening of diverse germplasm through whitefly (Bemisia tabaci mitotype Asia II) mediated artificial inoculation and PCR confirmed the 'PVR-1343' genotype as a resistance source against identified begomoviruses. To understand the genetic control of begomovirus resistant gene(s), segregating populations derived from crosses of 'PVR-1343' and four susceptible genotypes (MVSR-6711, Punjab Samrat, MBN-6242 and P-278) inoculated with SLCCNV, ToLCNDV and MI-Sq/To by whitefly in closed environment for three consecutive years (2018–2020). Disease scoring at 75 days after sowing rendered all F1 progenies as susceptible indicating recessive nature of resistance with no maternal or cytoplasmic effects. Chi-square analysis indicated a good fit of 9(S):3(MS):3(MR):1(R) ratio in F2 progenies of all crosses. Backcross of the F1’s to the resistant parent segregated into 1:1:1:1 ratio, while all progeny were susceptible in backcross of the F1’s with susceptible parent. Phenotypic segregation ratio of F2:3 confirmed the F2 genotypic ratio of 1:2:2:4:1:2:1:2:1. This substantiated that multiple begomovirus resistance in 'PVR-1343' is controlled by digenic recessive genes. Moreover, F2:3 progenies resistant to SLCCNV were also resistant to ToLCNDV and MI-Sq/To and vice versa, suggesting that common or tightly linked gene(s) might be involved in resistance to both viruses.

PKM2 allosteric converter: A self-assembly peptide for suppressing renal cell carcinoma and sensitizing chemotherapy

Stronger intrinsic Warburg effect and resistance to chemotherapy are the responses to high mortality of renal cell carcinoma (RCC). Pyruvate kinase M2 (PKM2) plays an important role in this process. Promoting PKM2 conversion from dimer to tetramer is a critical strategy to inhibit Warburg effect and reverse chemotherapy resistance. Herein, a PKM2 allosteric converter (PAC) is constructed based on the “in vivo self-assembly” strategy, which is able to continuously stimulate PKM2 tetramerization. The PAC contains three motifs, a serine site that is protected by enzyme cleavable β-N-acetylglucosamine, a self-assembly peptide and a AIE motif. Once PAC nanoparticles reach tumor site via the EPR effect, the protective and hydrophilic β-N-acetylglucosamine will be removed by over-expressed O-GlcNAcase (OGA), causing self-assembled peptides to transform into nanofibers with large serine (PKM2 tetramer activator) exposure and long-term retention, which promotes PKM2 tetramerization continuously. Our results show that PAC-induced PKM2 tetramerization inhibits aberrant metabolism mediated by Warburg effect in cytoplasm. In this way, tumor proliferation and metastasis behavior could be effectively inhibited. Meanwhile, PAC induced PKM2 tetramerization impedes the nuclear translocation of PKM2 dimer, which restores the sensitivity of cancer cells to first-line anticancer drugs. Collectively, the innovative PAC effectively promotes PKM2 conversion from dimer to tetramer, and it might provide a novel approach for suppressing RCC and enhancing chemotherapy sensitivity.

Analysis of HIV-1 envelope cytoplasmic tail effects on viral replication

Trimers of the HIV-1 envelope (Env) protein perform receptor binding and virus-cell fusion functions during the virus life cycle. The cytoplasmic tail (CT) of Env forms an unusual baseplate structure, and is palmitoylated, rich in arginines, carries trafficking motifs, binds cholesterol, and interacts with host proteins. To dissect CT activities, we examined a panel of Env variants, including CT truncations, mutations, and an extension. We found that whereas all variants could replicate in permissive cells, viruses with CT truncations or baseplate mutations were defective in restrictive cells. We also identified a determinant in HIV-1 amphotericin sensitivity, and characterized variants that escape amphotericin inhibition via viral protease-mediated CT cleavage. Results additionally showed that full-length, his tagged Env can oligomerize and be co-assembled with CT truncations that delete portions of the baseplate, host protein binding sites, and trafficking signals. Our observations illuminate novel aspects of HIV-1 CT structure, interactions, and functions.

Integrated analysis of metabolome and transcriptome reveals the cytoplasmic effects of CMS-D2 on pollen fertility resulting from disrupted lipid metabolism.

Using cytoplasmic male sterility of Gossypium harknesii (CMS-D2) is an economical and effective method to produce cotton hybrids. However, the detrimental cytoplasmic effects of CMS-D2 on pollen fertility and fiber yields greatly limit the further development of three-line hybrid cotton in China. In this study, an integrated non-targeted metabolomics and transcriptome analysis was performed on mature pollens of maintainer line NB, isonuclear alloplasmic near-isogenic restorer lines NH and SH under two environments. A total of 820 metabolites were obtained, of which lipids and lipid-like molecules were the most, followed by organic acids derivatives, phenylpropanoids, and polyketides. Transcriptome analysis revealed significantly more differentially expressed genes (DEGs) in SH versus NH both in Anyang and Jiujiang, and most of the DEGs were significantly upregulated. Further KEGG analysis showed that most DEGs were enriched in the biosynthesis of unsaturated fatty acids, phenylalanine metabolism, and phagosome. Based on the weighted gene co-expression network analysis, totally 74 hub genes were also identified, of which three transcription factors, i.e., WRKY22, WRKY53, and ARF18 were significantly upregulated in SH and may play a negative regulatory role in pollen development by directly or indirectly regulating the jasmonic acid synthesis and signal transduction. Moreover, we found that the negative effects of CMS-D2 cytoplasm on pollen fertility were mainly due to disturbed lipid metabolism, especially the metabolic balance of unsaturated fatty acids, ultimately resulting in the decline of pollen fertility. Meanwhile, in the presence of CMS-D2 sterile cytoplasm, the cytoplasmic-nucleus interaction effects generated a substantial quantity of flavonoids involved in the fertility restoration process. This study preliminarily clarified some of the reasons for the negative effects of CMS-D2 cytoplasm on pollen fertility, and our results will provide an important theoretical reference for further breeding and improvement of three-line hybrid cotton in the future.

Inheritance of resistance to three endemic viral diseases of cowpea in Nigeria

ABSTRACT Mosaic diseases, caused by bean common mosaic virus-blackeye cowpea mosaic strain (BCMV-BlCM), southern bean mosaic virus (SBMV), and cucumber mosaic virus (CMV), hamper the productivity of cowpea (Vigna unguiculata (L.) Walp.). Under single or mixed infections, these endemic viruses significantly reduce cowpea yield in sub-Saharan Africa. Planting resistant varieties is the most effective control method. Knowledge of the mode of inheritance of viral resistance is crucial in developing resistant varieties. Inheritance of resistance to BCMV-BlCM, SBMV, and CMV was investigated in two improved cowpea breeding lines. For BCMV-BICM, crosses were made between resistant IT97K-1042-3 (female) and susceptible IT99K-1060 (male); for SBMV, between resistant IT98K-1092-1 (male) and susceptible IT99K-1060 (female); and for CMV, between tolerant IT98K-1092-1 (female) and susceptible IT99K-573-1-1 (male). The F1 progenies were advanced to F2, and some F1 plants were backcrossed to the two parental lines. Reciprocal crosses were made and the 7-day-old seedlings of P1, P2, F1, F2, BCP1, and BCP2 were phenotyped by mechanical inoculation with BCMV-BlCM, SBMV, and CMV under screenhouse conditions. Data on disease incidence and severity were taken at weekly intervals for 5-week post-inoculation. Virus infections were confirmed via antigen-coated plate enzyme-linked immunosorbent assay or reverse transcription-polymerase chain reaction. Chi-square analysis of the genetic segregation indicated that a recessive gene pair in IT97K-1042-3 controlled the inheritance of resistance to BCMV-BlCM. Duplicate dominant genes conditioned the resistance to SBMV and tolerance to CMV in IT98K-1092-1. The backcrosses confirmed the monogenic and digenic inheritance patterns, whereas reciprocal crosses indicated absence of cytoplasmic effects.

Radiation-Induced Bystander Effect and Cytoplasmic Irradiation Studies with Microbeams.

Simple SummaryMicrobeams are useful tools in studies on non-target effects, such as the radiation-induced bystander effect, and responses related to cytoplasmic irradiation. A micrometer or even sub-micrometer-level beam size enables the precise delivery of radiation energy to a specific target. Here we summarize the observations of the bystander effect and the cytoplasmic irradiation-related effect using different kinds of microbeam irradiators as well as discuss the cellular and molecular mechanisms that are involved in these responses. Non-target effects may increase the detrimental effect caused by radiation, so a more comprehensive knowledge of the process will enable better evaluation of the damage resulting from irradiation.Although direct damage to nuclear DNA is considered as the major contributing event that leads to radiation-induced effects, accumulating evidence in the past two decades has shown that non-target events, in which cells are not directly irradiated but receive signals from the irradiated cells, or cells irradiated at extranuclear targets, may also contribute to the biological consequences of exposure to ionizing radiation. With a beam diameter at the micrometer or sub-micrometer level, microbeams can precisely deliver radiation, without damaging the surrounding area, or deposit the radiation energy at specific sub-cellular locations within a cell. Such unique features cannot be achieved by other kinds of radiation settings, hence making a microbeam irradiator useful in studies of a radiation-induced bystander effect (RIBE) and cytoplasmic irradiation. Here, studies on RIBE and different responses to cytoplasmic irradiation using microbeams are summarized. Possible mechanisms related to the bystander effect, which include gap-junction intercellular communications and soluble signal molecules as well as factors involved in cytoplasmic irradiation-induced events, are also discussed.

Genetic and genomic analysis of oxygen consumption in mice.

We estimated genetic parameters for oxygen consumption (OC), OC per metabolic body weight (OCMBW) and body weight at three through 8 weeks of age in divergently selected mice populations, with an animal model considering maternal genetic, common litter environmental and cytoplasmic inheritance effects. Cytoplasmic inheritance was considered based on maternal lineage information. With respect to OC, estimated direct heritability was moderate (0.32) and the estimated proportion of the variance of cytoplasmic inheritance effects to the phenotypic variance was very low (0.01), implying that causal genes for OC could be located on autosomes. To assess this hypothesis, we attempted to identify possible candidate causal genes through selective signature detection with the results of pooled whole-genome resequencing using pooled DNA samples from high and low OC mice. We made a list of possible candidate causal genes for OC, including those relating to electron transport chain and ATP-binding proteins (Ndufa12, Sdhc, Atp10b, etc.), Prr16 encoding Largen protein, Cry1 encoding a key component of the circadian core oscillator and so on. The results, although careful interpretation must be required, could contribute to elucidate the genetic mechanism of OC, an indicator for maintenance energy requirement, and therefore feed efficiency.

Application of 3D-volumetric analysis and hyperspectral imaging systems for investigation of heterosis and cytoplasmic effects in pepper

Compared with the substantial amount of genomics data generated in recent years, phenotypic data availability for crops is largely restricted in spectrum and quantity. High-throughput phenotyping (HTP) platforms have been developed to overcome this limitation, not only by enhancing the speed and accuracy of phenotyping but also by expanding the range of evaluable traits through integration of various imaging systems. Three-dimensional (3D) imaging enables non-destructive estimation of plant volume and structure. Hyperspectral imaging (HSI) generates reflectance data for a broad range of wavelengths that are associated with diverse physiological traits. We performed a pilot study to apply 3D and HSI for investigation of heterosis and cytoplasmic effects that have been evaluated previously based on manually analyzable traits. The plant volumes estimated from 3D images by a customized pipeline quantitatively showed heterosis in three cross combinations between genetically distant pepper (Capsicum annuum) accessions. The normalized difference vegetation index (NDVI) derived from HSI reflectance data also showed differences between parental and F1 lines. The cytoplasmic effects investigated by comparison of F1 lines derived from reciprocal crosses was subtle and thus was not detected in plant volume or NDVI values. However, the difference between F1 lines was detected in a subset of cross combinations at a specific developmental stage based on reflectance for wavelength ranges selected as the most relevant. The results showed the potential utility of HSI data recorded throughout the plant life-span for analysis of cytoplasmic effects. The present study demonstrated the applicability of a HTP platform integrated with 3D and HSI systems for evaluation of combining ability in crops.

Inheritance peculiarities of resistance to Septoria leaf spot on sunflower in F1 hybrids

Goal. To find out the peculiarities of inheritance of the resistance level to Septoria leaf spot by sunflower hybrids of the first generation obtained from crossing the lines with different disease resistance.
 Methods. Field assessment of resistance to pathogen of sunflower breeding lines and F1 hybrids obtained from crossing the lines. 
 Results. Differences in Septoria leaf spot resistance in sunflower breeding lines on a stationary infectious background were found. Among the lines, the most affected by Septoria leaf spot was the line ZL58A and had from 88.8% to 97.9% of plants with symptoms of the disease. ZL70A and ZL78A lines were significantly less affected by desease than the previous line. Healthy plants for two years of research in these samples were from 73.3% to 87.5%. The HAR7 line was close to the previous two lines, the number of diseased plants varied in different years from 16.7% to 40%, and without lesions from 60% to 83.3%. This line had some differences in the intensity of the disease during the two experimental years. As a result of the study, it was found that the hybrid ZL58A × HAR7 was most affected by Septoria leaf spot. The number of affected plants in both years of research ranged from 80.8% to 90.3%. This sample was susceptible to the disease, as well as the maternal line ZL58A. Hybrids of the first generation of the combinations ZL70A × HAR7 and ZL78A × HAR7 were the least affected. In two years of research, these hybrids had between 60% and 79% of healthy plants and 21% to 40% with symptoms of the disease, respectively. These hybrids are relatively resistant to the disease, as well as their maternal and paternal components.
 Conclusions. The type of inheritance of resistance to Septoria leaf spot by sunflower hybrids is revealed implies the presence of cytoplasmic effects or control of this trait by nuclear genes where susceptibility to the disease is the dominant feature and resistance is recessive.

Cytoplasmic effects of CMS-D2 in upland cotton

<p indent="0mm">Two sets of isonuclear alloplasmic near-isogenic restorer lines of <italic>Gossypium harknessii</italic> were planted in cotton production areas of the Yellow River (Anyang, Henan) and Yangtze River (Jiujiang, Jiangxi) basins, and comparative analyses of seedling growth, leaf photosynthetic parameters, anther development, cotton yield as well as its constituent factors, and fiber quality traits were performed to clarify the cytoplasmic effects of CMS-D2 in upland cotton. The results are as follows: (i) sterile cytoplasm did not affect cotton seedling growth and most fiber quality traits. (ii) The net photosynthetic rate of the sterile cytoplasmic restorer lines was significantly higher at the seedling stage but lower after the blooming stage when compared to the fertile cytoplasmic restorer lines. (iii) The anther fertility of the sterile cytoplasmic restorer lines under high-temperature stress was significantly lower than that of the fertile cytoplasmic restorer lines, which was mainly manifested in a significant reduction in pollen amount, pollen activity and vitality. (iv) The sterile cytoplasm negatively affected yield traits, which was mainly manifested in a significant reduction in boll number per plant and lint percentage. (v) In general, the negative effects of sterile cytoplasm on net photosynthetic rate, anther development and cotton yield were more obvious in cotton production area of the Yangtze River basin where summer temperatures are higher. This paper systematically explored the effects of CMS-D2 cytoplasm on the main traits of upland cotton, and the results of this study are of great significance for the breeding and improvement of cytoplasmic sterile “three-line” hybrid cotton.

Detection of Maternal and Cytoplasmic Effects on Resistance to Zymoseptoria tritici in Durum Wheat.

Septoria tritici blotch (STB) is a major disease problem of wheat worldwide. To optimize the introgression of resistance genes in elite genotypes throughout traditional or molecular breeding programs, a full understanding of the quantitative inheritance of resistance to Zymoseptoria tritici, plant height (PH), and thousand kernel weight (TKW) is needed. In this study, maternal and cytoplasmic effects of resistance to STB were investigated using P1 (susceptible, high-yielding line) and P2 (resistant, low-yielding line) durum wheat lines and their F1, RF1, F2, RF2, BC1, RBC1, BC2, and RBC2 progeny, assessed for resistance to STB during three growing seasons. Duncan mean's analysis revealed significant differences between generation means for STB, PH, and TKW. The two parents had an extreme pattern. The F1 and RF1 segregated close to their respective parents, suggesting the presence of cytoplasmic and maternal genetic effects for Z. tritici resistance, PH, and TKW. Separate generation mean's analysis confirmed the results of the Duncan test. A three-parameter model was found to be not adequate for all traits in all three growing years; while a digenic epistatic model with cytoplasmic or/and maternal effect was adequate for all cases. Narrow-sense heritability was in the range of 50–60%, 30–69%, and 28–31% for STB, PH, and TKW, respectively. For STB, high heritability and the presence of fixable epistatic effect is encouraging and could lead to creating varieties with the right female parent to exploit cytoplasmic and maternal effects in order to improve resistance to Z. tritici in durum wheat.

Effect of sterile cytoplasms on content of absolutely dry matter in the grain sorghum hybrids

Analysis of absolutely dry matter (ADM) accumulation is important indicator of productivity of crop plants. For three seasons, we investigated the effect of sterile cytoplasms on content of ADM in the F1 hybrids of grain sorghum obtained on the basis of two series of alloplasmic iso-nuclear CMS-lines: (1) with A3, A4, and 9E cytoplasms and (2) with 9E and M35-1A cytoplasms. For the first time, the effect of the type of sterile cytoplasm on content of ADM in the F1 sorghum hybrids was shown. In each season, A3 cytoplasm reduced ADM in the F1 hybrids at the “tillering – heading” stage, whereas 9E cytoplasm increased ADM at the “heading – complete maturity” stage. The most significant differences were observed under drought conditions. These data indicate the genetic influence of cytoplasm on assimilation capacity of sorghum hybrids and tolerance to drought stress.