The extraction of high-quality RNA from cotton (Gossypium spp.) is challenging because of the presence of high polyphenolics, polysaccharides, quinones, and other secondary metabolites. A ...high-throughput RNA extraction protocol is a prerequisite. This Triton-X-100-based RNA extraction method utilizes Polyvinyl pyrrolidone polymer (PVPP) treatment which efficiently removes phenolics, and the application of Lithium chloride (LiCl) has been found that successfully precipitated the high-quality RNA from cotton tissue. Cytoplasmic male sterility (CMS) is a maternally inherited trait associated with specific mitochondrial genome rearrangements or mutations. The suitability of RNA extracted from Cotton CMS lines was assessed. cDNA was synthesized from RNA and assayed for mitochondrial genes (cox3, nad3, nad9) associated with male sterility. This paper discuss the advantages and limitation of this protocol over existing protocol for RNA extraction for polyphenolics-rich plant tissue.
Display omitted
•Efficient protocol with a minimum amount of plant material is required.•Extraction protocol is equally useful for plants having diverse lipids/fatty acids, polysaccharides, and polyphenols.•High throughput protocol is simple, economic, less time-consuming, efficient and applicable to cytoplasmic genome analysis.
Plant cytoplasmic male sterility is caused by mutations and rearrangements of mitochondrial genes. It serves as a significant way to utilize hybrid vigor to enhance crop yield. Ogu CMS is a natural ...cytoplasmic male sterility type discovered in radishes, being successfully transferred to rapeseed and cruciferous vegetables. However, current studies lack depth in exploring the molecular mechanisms of its male sterility. In this study, we confirmed orf138 is the causal gene for Ogu CMS through genetic transformation in Arabidopsis. Transcriptome analysis of aborted anthers in different stages suggested differentially expressed genes (DEGs) are mainly enriched in pathways such as glycerophospholipid metabolism and arginine and proline metabolism. It reveals that key genes involved in lipid metabolism pathways are significantly down-regulated in the sterile line (OguA), including BnaGPAT1, localized within the tapetum mitochondrial and endoplasmic reticulum. This could lead to changes in the metabolism of substances like acylglycerols within the tapetum, causing disruptions in lipid metabolism. This is consistent with morphological and subcellular structural changes in the tapetum and microspore cells as observed in the transmission electron microscopy. This abnormal lipid metabolism may trigger specific ROS accumulation in an oxidative stress response, ultimately leading to aborted microspore. Our study based on transcriptome has deepened our understanding of the molecular mechanisms in Ogu CMS.
The discovery of a wild abortive-type cytoplasmic male sterile line and the breeding of its restorer line have led to the commercialization of three-line hybrid rice, which has contributed greatly to ...global food security. However, the molecular mechanisms underlying fertility abortion and the restoration of wild abortive-type cytoplasmic male sterile lines largely remain elusive. In this study, we cloned a restorer gene, Rf20, following a genome-wide association study analysis of the core parent lines of three-line hybrid rice. We found that Rf20 was present in all core parental lines, but different haplotypes and structural variants of its gene resulted in differences in Rf20 expression levels between sterile and restored lines. Rf20 could restore fertility in the wild abortive-type cytoplasmic male sterile line and was found to be responsible for fertility restoration in some cytoplasmic male sterile lines under high temperature. In addition, we found that Rf20 encodes a pentatricopeptide repeat protein that competes with WA352 for binding with COX11. This interaction enhances COX11's function as a scavenger of reactive oxygen species, which in turn restores pollen fertility. In this study, a new model of pentatricopeptide repeat proteins involved in the fertility recovery of cytoplasmic male sterile lines was proposed, which provides an important theoretical basis for the breeding of strong restorer lines and for overcoming high-temperature fertility recovery of some three-line sterile lines.The discovery of a wild abortive-type cytoplasmic male sterile line and the breeding of its restorer line have led to the commercialization of three-line hybrid rice, which has contributed greatly to global food security. However, the molecular mechanisms underlying fertility abortion and the restoration of wild abortive-type cytoplasmic male sterile lines largely remain elusive. In this study, we cloned a restorer gene, Rf20, following a genome-wide association study analysis of the core parent lines of three-line hybrid rice. We found that Rf20 was present in all core parental lines, but different haplotypes and structural variants of its gene resulted in differences in Rf20 expression levels between sterile and restored lines. Rf20 could restore fertility in the wild abortive-type cytoplasmic male sterile line and was found to be responsible for fertility restoration in some cytoplasmic male sterile lines under high temperature. In addition, we found that Rf20 encodes a pentatricopeptide repeat protein that competes with WA352 for binding with COX11. This interaction enhances COX11's function as a scavenger of reactive oxygen species, which in turn restores pollen fertility. In this study, a new model of pentatricopeptide repeat proteins involved in the fertility recovery of cytoplasmic male sterile lines was proposed, which provides an important theoretical basis for the breeding of strong restorer lines and for overcoming high-temperature fertility recovery of some three-line sterile lines.
Photoperiod-sensitive cytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm under long-day (LD) photoperiods (≧15 h) has been proposed as a two-line system for producing hybrid ...varieties of common wheat (Triticum aestivum). PCMS lines are maintained by self-pollination under short-day (SD) conditions (＜15 h), while outcrossing PCMS plants to a T. aestivum pollinator line under LD conditions produces hybrid seeds. In this system, it is not necessary to have maintainer lines in order to sustain the PCMS lines. Several promising elite PCMS lines with a Japanese wheat cultivar ‘Fukuotome’ genetic background have been developed; these lines show high cross-pollination fertility and high male sterility under LD conditions, and high seed fertility under SD conditions. In addition, the European wheat cultivar ‘Fortunato’ was found to be suitable for use in the PCMS system. Through the use of the PCMS elite lines and the selected pollinator line, F1 seeds have been produced under LD conditions in Hokkaido, Japan, and the agronomic characters of F1 hybrids have been examined under SD conditions in Fukui, Japan. The results indicate the practicality of using this PCMS system for hybrid wheat production in Japan.
In sorghum Sorghum bicolor (L.) Moench, combining ability and heterosis analysis are commonly used to evaluate superior parental lines and to screen for strongly heterotic hybrids, which helps in ...sorghum variety selection and breeding. In this context, combining ability and heterosis analysis were assessed using 14 restorer lines and seven cytoplasmic male sterile (CMS) lines in 2019 and 2020. The analysis of variance of all cross combinations had highly significant differences for all characters studied, which indicated a wide variation across the parents, lines, testers, and crosses. Combining ability analysis showed that the general combining ability (GCA) and specific combining ability (SCA) of the different parents were differed significantly among different traits. Most combinations with high SCA also showed high GCA in their parent lines. The heritability in the narrow sense of grain weight per panicle and grain yield was relatively low, indicating that the ability of these traits to be directly inherited by offspring was weak, that they were greatly affected by the environment. The better-parent heterosis for plant height, grain weight per panicle, panicle length, and 1000-grain weight was consistent with the order of mid-parent heterosis from strong to weak. The GCA effects of two lines 10480A, 3765A and three testers 0-30R, R111, and JY15R were significant for the majority of the agronomic traits including grain yield and might be used for improving the yield of grains in sorghum as parents of excellent specific combining ability. Seven strongly heterotic F.sub.1 hybrids were screened; of these, hybrids 3765A x R111, 1102A x L2R, and 3765A x JY15R showed significant increases in seed iristectorigenin A content and will feature into the creation of new sorghum varieties rich in iristectorigenin A.
Restorer-of-fertility (Rf) genes encode pentatricopeptide repeat (PPR) proteins that are targeted to mitochondria where they specifically bind to transcripts that induce cytoplasmic male sterility ...and repress their expression. In searching for a molecular signature unique to this class of proteins, we found that a majority of known Rf proteins have a distinct domain, which we called RfCTD (Restorer-of-fertility C-terminal domain), and its presence correlates with the ability to induce cleavage of the mitochondrial RNA target. A screen of 219 angiosperm genomes from 123 genera using a sequence profile that can quickly and accurately identify RfCTD sequences revealed considerable variation in RFL/RfCTD gene numbers across flowering plants. We observed that plant genera with bisexual flowers have significantly higher numbers of RFL genes compared to those with unisexual flowers, consistent with a role of these proteins in restoration of male fertility. We show that removing the RfCTD from the RFL protein RNA PROCESSING FACTOR 2-nad6 prevented cleavage of its RNA target, the nad6 transcript, in Arabidopsis thaliana mitochondria. We provide a simple way of identifying putative Rf candidates in genome sequences, new insights into the molecular mode of action of Rf proteins and the evolution of fertility restoration in flowering plants.
In many plant species, male-sterile female lines with cytoplasmic male sterility (CMS) or nuclear-controlled environment-sensitive genic male sterility (EGMS) have long been used to efficiently ...produce hybrids that harness hybrid vigor or heterosis. However, the underlying molecular mechanisms for these applications have only recently been uncovered in a few species. We provide here an update on the understanding of cytoplasmic–nuclear communication based on the discovery of mitochondrial CMS genes and their corresponding nuclear fertility determinants. Recent findings that uncover diverse mechanisms such as epigenetic, transcriptional, and post-transcriptional controls of EGMS by temperature and photoperiod signals are also reviewed. Furthermore, translational research that applies basic knowledge of plant male fertility control to hybrid seed production practice is highlighted.
CMS lines used for three-line hybrid system can only be recovered by a specific restorer of male fertility (Rf) gene.
CMS genes may be formed during evolution through gene duplication and multi-recombination, and the corresponding nuclear Rf genes appear to have undergone coevolution.
EGMS lines, mainly caused by nuclear gene mutations, have been developed for the two-line breeding system, particularly in rice.
Complex and diverse interactions between genetic control and environmental temperature and photoperiods may determine plant male fertility.
The identification and utilization of nuclear male-sterile genes in combination with new technologies have achieved successful male fertility control of crops.
In plants, male sterility can be caused either by mitochondrial genes with coupled nuclear genes or by nuclear genes alone; the resulting conditions are known as cytoplasmic male sterility (CMS) and ...genic male sterility (GMS), respectively. CMS and GMS facilitate hybrid seed production for many crops and thus allow breeders to harness yield gains associated with hybrid vigor (heterosis). In CMS, layers of interaction between mitochondrial and nuclear genes control its male specificity, occurrence, and restoration of fertility. Environment-sensitive GMS (EGMS) mutants may involve epigenetic control by noncoding RNAs and can revert to fertility under different growth conditions, making them useful breeding materials in the hybrid seed industry. Here, we review recent research on CMS and EGMS systems in crops, summarize general models of male sterility and fertility restoration, and discuss the evolutionary significance of these reproductive systems.
Celery (Apium graveolens L.) is an important leafy vegetable worldwide. The development of F1 hybrids in celery is highly dependent on cytoplasmic male sterility (CMS) because emasculation is ...difficult. In this study, we first report a celery CMS, which was found in a high-generation inbred line population of the Chinese celery “tanzhixiangqin”. Comparative analysis, following sequencing and assembly of the complete mitochondrial genome sequences for this celery CMS line and its maintainer line, revealed that there are 21 unique regions in the celery CMS line and these unique regions contain 15 ORFs. Among these ORFs, only orf768a is a chimeric gene, consisting of 1497 bp sequences of the cox1 gene and 810 bp unidentified sequences located in the unique region, and the predicted protein product of orf768a possesses 11 transmembrane domains. In summary, the results of this study indicate that orf768a is likely to be a strong candidate gene for CMS induction in celery. In addition, orf768a can be a co-segregate marker, which can be used to screen CMS in celery.
Cytoplasmic male‐sterile (CMS) lines are being used to produce hybrid seeds. Thus far, four CMS sources in soybean Glycine max (L.) Merr. have been reported in China. However, they are not sufficient ...or efficient in meeting the requirements of commercial soybean hybrid seed production. In this study, 33 varieties were tested for CMS using 45 crosses among 37 landraces and 17 annual wild soybean accessions (Glycine soja Sieb. et Zucc.). The cross of N23661 × N23658 showed partial to complete male sterility in backcross generations, while the corresponding reciprocal cross showed normal male fertility. Thus, the cytoplasm of N23661 is male‐sterile, the continuously backcrossed line is a male‐sterile line (designated NJCMS4A), and N23658 is its maintainer (designated NJCM4B). The male fertility of NJCMS4A was restored by another accession, Nansheng9403. Accordingly, NJCMS4A along with its maintainer and restorer composes a complete set of three lines for producing hybrid soybean. Using mitochondrial markers and sequence analyses, NJCMS4A is a CMS line with its cytoplasm not identical to the four previously reported CMS sources in soybean.
PDF
