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黄单胞杆菌水稻变种(Xanthomonas oryzae pv.oryzae,Xoo)引起的水稻白叶枯病是一个世界性的严重病害。疣粒野生稻(Oryzae meyeriana)对Xoo具有高度抗性,但其抗性机制仍不清楚。本文以抗病的疣粒野生稻和感病的水稻品种大粒香为材料,研究了Xoo侵染对叶片病斑、叶绿体超微结构、光合系统活性和木质部超微结构的影响。结果表明,多种Xoo生理小种导致的疣粒野生稻叶片病斑长度都明显短于大粒香叶片的病斑长度。Xoo病菌侵染显著破坏了大粒香的叶绿体结构,明显抑制了其光合活性,而疣粒野生稻中的变化要轻得多。通过电镜切片,发现疣粒野生稻叶片导管内存在大量的Xoo病菌,这表明Xoo能够侵染疣粒野生稻且能够在叶片内增殖。病菌的侵染诱导了疣粒野生稻木质部次生细胞壁的增厚,抑制了病菌通过导管纹孔向邻近细胞的进一步侵染,这种反应可能参与了疣粒野生稻对Xoo的抗性。
Rice bacterial blight caused by Xanthomonas oryzae pv. Oryzae (Xoo) is a worldwide serious disease. Oryzae meyeriana is highly resistant to Xoo but its mechanism of resistance remains unclear. In this paper, the effects of Xoo infection on leaf spot, chloroplast ultrastructure, photosynthetic system activity and ultrastructure of xylem were studied using resistant wart wild rice and susceptible rice grain. The results showed that the lesion length of the leaves of warty wild rice caused by a variety of Xoo race was significantly shorter than the lesion length of the large seedling leaves. Xoo pathogen infection significantly damaged the chloroplast structure of C. occidentalis and significantly inhibited its photosynthetic activity, while the changes in O. wativa were much lighter. Through electron microscopy, we found that a large number of Xoo germs were found in the leaves of warty wild rice leaves, indicating that Xoo could infect warty wild rice and could proliferate inside the leaves. Infection of pathogen induced thickening of the secondary cell wall of xylem in Warty Wild Rice, and inhibited the further infection of pathogenic bacteria to adjacent cells through the conduit pore. This reaction may be involved in the resistance of Wool Wild Rice to Xoo.