Morphological Structure and Transcriptome Comparison of the Cytoplasmic Male Sterility Line in Brassica napus (SaNa-1A) Derived from Somatic Hybridization and Its Maintainer Line SaNa-1B

Abstract

SaNa-1A is a novel cytoplasmic male sterility (CMS) line in Brassica napus derived from progenies of somatic hybrids between B.napus and Sinapis alba, and SaNa-1B is the corresponding maintainer line. In this study, phenotypic differences of floral organs between CMS and the maintainer lines were observed. By microscope observation in different anther developmental stages of two lines, we found the anther development in SaNa-1A was abnormal since the tetrad stage, and microspore development was ceased during the uninucleate stage. Transcriptomic sequencing for floral buds of sterile and fertile plants were conducted to elucidate gene expression and regulation caused by the alien chromosome and cytoplasm from S. alba. Clean tags obtained were assembled into 195,568 unigenes, and 7811 unigenes distributed in the metabolic and protein synthesis pathways were identified with significant expression differences between two libraries. We also observed that genes participating in carbon metabolism, tricarboxylic acid cycle, oxidative phosphorylation, oxidation-reduction system, pentatricopeptide repeat, and anther development were downregulated in the sterile line. Some of them are candidates for researches on the sterility mechanism in the CMS material, fertility restoration, and improvement of economic traits in the maintainer line. Further research on the tags with expressional specificity in the fertile line would be helpful to explore desirable agronomic traits from wild species of rapeseed.

Transcriptome profiling of differentially expressed genes in cytoplasmic male-sterile line and its fertility restorer line in pigeon pea (Cajanus cajan L.)

“…Two DEGs Ccajan_13673_c0_g1_i1 and Cca-jan_41295_c0_g1_i1 encoding cytochrome c oxidase subunit 6b and subunit 1 were 5.98-fold and 6.46-fold downregulated in the AKCMS11 (Table 4). This was in accordance with the earlier reports in chili pepper, cotton, Brassica napus and beet [59,93,123,129]. Hence, altered expression of cox 6 might have resulted in decreased ATP synthesis and disrupted the pollen formation in this crop.…”

“…We identified, 2 DEGs participating in the TCA cycle, Ccajan_64232_c0_g1_i1 encoding malate dehydrogenase and Ccajan_35485_c0_g1_i1 encoding succinate-CoA synthetase (Table 4). According to the previous reports in cotton, Brassica napus and cabbage lower expression of TCA related genes causes pollen abortion and are responsible for CMS [93,123,124]. These observations suggest that alterations in the energy-yielding metabolic pathways inhibits pollen development and may be the cause of CMS.…”

Comparative Analysis of the Cytology and Transcriptomes of the Cytoplasmic Male Sterility Line H276A and Its Maintainer Line H276B of Cotton (Gossypium barbadense L.)

“…Microspore degradation is associated with abnormal programmed cell death (PCD) of the tapetum, which is responsible for supplying nutrition to the developing microspore [ 2 ]. Advanced or delayed degradation of the tapetum can lead to the degradation of microspores in plants, such as Brassica napus [ 3 ], cabbage [ 4 ], and Capsicum annuum [ 5 ]. Microspore development is a complex process, and identification of the abortion stage during exploration of the molecular mechanisms of CMS could facilitate elimination of the interference from unrelated genes.…”

De novo-based transcriptome profiling of male-sterile and fertile watermelon lines

“…Notably, Ms-cd1 mutant cabbage producing collapsed pollen showed repression of various ion transporters in floral buds [ 45 ]. Galactosidase is a cell wall modifying enzyme that is involved in microspore development [ 46 ]. The anther surface and pollen exine are composed of cutin and intra- and epi-cuticular waxes [ 47 ].…”