A rice β-1,3-glucanase gene Osg1 is required for callose degradation in pollen development.
Plant β-1,3-glucanases are involved in plant defense and development. In rice (Oryza sativa), 14 genes encoding putative β-1,3-glucanases have been isolated and sequenced. However, only limited information is available on the function of these β-1,3-glucanase genes. In this study, we report a detailed functional characterization of one of these genes, Osg1. Osg1 encodes a glucanase carrying no C-terminal extension. Osg1 was found to be expressed throughout the plant and highly expressed in florets, leaf sheaths, and leaf blades. Investigations using real-time PCR, immunocytochemical analysis, and a GUS-reporter gene driven by the Osg1 promoter indicated that Osg1 was mainly expressed at the late meiosis, early microspore, and middle microspore stages in the florets. To elucidate the role of Osg1, we suppressed expression of the Osg1 gene by RNA interference in transgenic rice. The silencing of Osg1 resulted in male sterility. The pollen mother cells appeared to be normal in Osg1-RI plants, but callose degradation was disrupted around the microspores in the anther locules of the Osg1-RI plants at the early microspore stage. Consequently, the release of the young microspores into the anther locules was delayed, and the microspores began to degenerate later. These results provide evidence that Osg1 is essential for timely callose degradation in the process of tetrad dissolution.
Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
Linglin
L
Wan
Wenjun
W
Zha
Xiaoyan
X
Cheng
Chuan
C
Liu
Lu
L
Lv
Caixiang
C
Liu
Zhanqi
Z
Wang
Bo
B
Du
Rongzhi
R
Chen
Lili
L
Zhu
Guangcun
G
He
D001483:Base Sequence; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000235:genetics / Q000378:metabolism*; D005936:Glucans / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000201:enzymology* / Q000254:growth & development*; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism
D005936:Glucans; D018749:RNA, Plant; C048306:callose; D004693:Glucan Endo-1,3-beta-D-Glucosidase