Morphological characteristics and transcriptome analysis at different anther development stages of the male sterile mutant MS7–2 in Wucai (Brassica campestris L.)

Abstract

Background The discovery of male sterile materials is of great significance for the development of plant fertility research. Wucai (Brassica campestris L. ssp. chinensis var. rosularis Tsen) is a variety of non-heading Chinese cabbage. There are few studies on the male sterility of wucai, and the mechanism of male sterility is not clear. In this study, the male sterile mutant MS7–2 and the wild-type fertile plant MF7–2 were studied. Results Phenotypic characteristics and cytological analysis showed that MS7–2 abortion occurred at the tetrad period. The content of related sugars in the flower buds of MS7–2 was significantly lower than that of MF7–2, and a large amount of reactive oxygen species (ROS) was accumulated. Through transcriptome sequencing of MS7–2 and MF7–2 flower buds at three different developmental stages (a–c), 2865, 3847, and 4981 differentially expressed genes were identified in MS7–2 at the flower bud development stage, stage c, and stage e, respectively, compared with MF7–2. Many of these genes were enriched in carbohydrate metabolism, phenylpropanoid metabolism, and oxidative phosphorylation, and most of them were down-regulated in MS7–2. The down-regulation of genes involved in carbohydrate and secondary metabolite synthesis as well as the accumulation of ROS in MS7–2 led to pollen abortion in MS7–2. Conclusions This study helps elucidate the mechanism of anther abortion in wucai, providing a basis for further research on the molecular regulatory mechanisms of male sterility and the screening and cloning of key genes in wucai.

Assessment of Cytomorphological Differences in Sorghum Fertility Restoration

“…Similar findings were observed in the Brassica anthers of MF7-2, which developed normally and possessed many plump pollen grains. The filaments of MS7-2 were short, and the anthers were abnormally degraded, with no obvious pollen grains on the surface [33]. The BTx623 s (wild-type sorghum) mature spikelet (sessile spikelet) contains three extruding yellow anthers and two stigmas with pollen grains.…”

“…Mutation in this locus leads to the replacement of amylose with amylopectin [38]. The starch deposition is controlled gametophytically, and hence fertility restoration in CMS plants is gametophytic in nature [18,19,33]. The findings in sorghum suggested that the deterioration of pollen grains was associated with an increase in reactive oxygen species (ROS) with a significant reduction in phospholipid levels.…”

Morphological characteristics of flower organs and in vitro micropropagation of male sterile lines of Lilium hybrids

“…Flow cytometry (FCM) and chromosome counting, as well as observation of morphological and physiological characteristics, are widely applied for determining ploidy levels in plants (Ferreira et al, 2021;Wang et al, 2021). Among them, chromosome counting is the most direct and accurate.…”

“…Thus, breeding of pollen-free lily varieties is an urgent need for promoting cut-flower lily production. In previous studies, new pollen-free varieties were developed mainly through traditional crossbreeding and mutagenesis breeding (Wang et al, 2021). Pollen-free F1 was produced through hybridisation, and a set of pollenfree genetic traits was established.…”