Phenotype characterisation and analysis of expression patterns of genes related mainly to carbohydrate metabolism and sporopollenin in male-sterile anthers induced by high temperature in wheat (Triticum aestivum)

Abstract

Male reproductive development in higher plants is highly sensitive to various stressors, including high temperature (HT). In this study, physiological male-sterile plants of wheat (Triticum aestivum L.) were established using HT induction. The physiological changes and expression levels of genes mainly related to carbohydrate metabolism and sporopollenin in male-sterile processes were studied by using biological techniques, including iodine–potassium iodide staining, paraffin sectioning, scanning electron microscopy (SEM) and fluorescent quantitative analysis. Results of paraffin sectioning and SEM revealed that parts of HT male-sterile anthers, including the epidermis and tapetum, were remarkably different from those of normal anthers. The expression levels of TaSUT1, TaSUT2, IVR1 and IVR5 were significantly lower than of normal anthers at the early microspore and trinucleate stages. The RAFTIN1 and TaMS26 genes may contribute to biosynthesis and proper ‘fixation’ of sporopollenin in the development of pollen wall; however, their expression levels were significantly higher at the early tetrad stage and early microspore stage in HT sterile anthers. The recently cloned MS1 gene was expressed at the early tetrad and early microspore stages but not at the trinucleate stage. Moreover, this gene showed extremely significant, high expression in HT sterile anthers compared with normal anthers. These results demonstrate that HT induction of wheat male sterility is probably related to the expression of genes related to carbohydrate metabolism and sporopollenin metabolism. This provides a theoretical basis and technological approach for further studies on the mechanisms of HT induction of male sterility.