The Relation between Anther's Nutrient Metabolism and Pollen Abortion of Male Sterile Lines in Lycium barbarum L.

[ Objective] This study deals with the relation between anther nutrient metabolism and pollen abortion of male sterile lines in Lycium barbarum L., and provides some theoretical references for the pollen abortion mechanism of male sterile lines in Lyciurn barbarurn L.. [Method] By using semi-thin section and cytochemistry technology, the accumulation and distribution of anther nutrient of male sterile and fertile lines in Lycium barbarum L. were observed and compared. [ Result] The result showed that after meiosis, starch grains in the connective parenchyma of anther decreased sharply, and starch grains in epidermis and endothecium were also greatly decreased, while nearly no lipid accumulated in tapetal cells in male sterile lines compared with the fertile lines. The tapetal cells and tetraspore had vacuoles appear successively, and then entered the degenerate process. During the degeneration stage of tapetal cells and tetraspore, starch grains in epidermis and endothecium were still in a smell number and in the connective parenchyme as well. [ Conclusion] The decrease of polysaccharide supplying in anther vascular leads to the disorder of mechanism of glycelipid transforming in tapetal ceils, which triggers the tapetal cells degenerating ahead of time, and the latter gives rise to callus wall failing to degenerate in time. Therefore, the tetrads disintegrate and disappear ultimately due to lack of nutrition.

Changes of Oxidative Stress and Soluble Sugar in Anthers Involve in Rice Pollen Abortion Under Drought Stress

Two rice maintaining lines with different drought tolerances, viz., Jin 23B （tolerant） and Zhenshan 97B （sensitive）, were used to study the oxidative stress and soluble sugar in rice anthers and pollen viability under drought stress during flowering stage. Higher antioxidant enzyme activities and lower malonaldehyde （MDA） content in rice anthers were observed in Jin 23B than in Zhenshan 97B under drought stress. Further, a great increase in the content of soluble sugar in rice anthers of Jin 23B was observed across the whole drought exposure, while Zhenshan 97B showed significant decrease in soluble sugar during 9-12 d after drought stress （DADS）. Accordingly, a marked decline of pollen fertility and activity, pollen numbers in an anther and pollen numbers on a stigma was observed in Zhenshan 97B, whereas little difference was found in Jin 23B. Thus, we suggest that pollen abortion caused by drought stress may be related with the reciprocity between oxidative stress and soluble sugar content in rice anthers.

Screening and Analysis of Proteins Interacting with TaPDK from Physiological Male Sterility Induced by CHA in Wheat

To further research the regulatory network of pyruvate dehydrogenase kinase （designated as TaPDK） in physiological male-sterility （PHYMS） of wheat induced by chemical hybridizing agent （CHA） SQ-1, an anther cDNA library was constructed, and the proteins interacting with TaPDK were screened via yeast two-hybrid technique. Subsequently, a few candidate proteins in nucleotide expression levels were detected by real-time quantitative PCR. Yeast-two hybrid screening was performed by mating yeast strain Y2HGold containing BD-TaPDK bait plasmid with yeast strain Y187 including anther cDNA library plasmid. Diploid yeast cells were plated on synthetic dropout nutrient medium （SD/-Ade/-His/-Leu/-Trp） （QDO）, and further were incubated on QDO medium containing AbA and X-α-Gal. The interactions between TaPDK and the proteins obtained from positive colonies were further confirmed by co-transformation validation. After plasmids DNA were extracted from blue colonies and sequenced, the sequences results were analyzed by bioinformatic methods. Finally, 24 colonies were obtained, including eight genes, namely non-specific lipid-transfer protein precursor （TanLTP）, polyubiquitin （TaPUbi）, glyceraldehyde-3-phosphate dehydrogenase, proliferating cell nuclear antigen （TaPCNA）, CBS domain containing protein （TaCBS）, actin, guanine nucleotide-binding protein beta subunit, chalcone synthase, and three new genes with unknown function. The results of quantitative RT-PCR showed that the expression levels of TanLTP, TaPUbi, and TaPCNA were obviously up-regulated in PHYMS anther, and TaCBS expression was only increased at the tricellular stage in PHYMS anther compared with in fertile lines. Whereas, the expression of TaPDK was obviously down-regulated in PHYMS lines. Collectively, these datas indicated that the majority of candidate proteins might be related to pollen abortion in PHYMS lines, which further suggested that TaPDK plays multiple roles in pollen development, besides participating in regulating pyruvate dehydrogenase complex activity.