Silencing of BnROP1 homologue gene leads to male sterility in Arabidopsis.

Based on previous analysis of microarray expression on Brassica napus homozygous pairs of dominant male sterile line, a differentially expressed Brassica napus gene (BnROP1) which is homologous to At3 G5 1300 (AtROP1) was selected. Method of fluorescent quantitative PCR was used to analyze the expression pattern of Bn-ROP1 in different tissues of B. napus, including root, stem, leaves, flower, pistil, stamen and silique. The results indicated that BnROP1 was highly expressed in fertile flower and stamen. On this basis, microRNA interference vector was constructed and then transformed into Arabidopsis thaliana by Agrobacterium, obtaining 12 transgenic seedlings. The phenotype of T₁ transgenic generation was observed during florescence. Most transgenic seedlings showed reduction or disappearance of siliques, no pollen, short filaments, deteriorated anther and microspore. These phenomena indicated that these seedlings were fully - sterile or semi - sterile. The fluorescence quantitative PCR experiments on T₂ generations of transgenic lines showed that the expression level of target gene decreased sig- nificantly. The correlation of transgenic male sterile phenotype and the silencing of ROP1 expressing indicated that ROP1 was not only promoting tip growth and maintaining growth polarity in pollen tubes but was also essential for plant fertility. [ABSTRACT FROM AUTHOR]