Chloroplast division

Chloroplasts are descendants of cyanobacteria and divide by binary fission. Several components of the division apparatus have been identified in the past several years and we are beginning to appreciate the plastid division process at a mechanistic level. In this review, we attempt to summarize the most recent developments in the field and assemble these observations into a working model of plastid division in plants.     

斜纹夜蛾多角体病毒包埋型病毒受体的鉴定

蔗糖密度梯度离心法提纯斜纹夜蛾核多角体病毒（＄Ｓｐｏｄｏｐｔｅｒａ　ｌｉｔｕｒａ　　ｍｕｌｔｉｎｕｃｌｅｏｃａｐｓｉｄ　ｎｕｃｌｅｏｐｏｌｙｈｄｒｏｖｉｒｕｓ,　ＳｐｌｔＭＮＰＶ）包埋型病毒粒子（ｐｏｌｙｈｅｄｒａ－ｄｅｒｉｖｅｄ　ｖｉｒｕｓ,ＰＤＶ）,以此病毒粒子作抗原,免疫家兔获得抗血清;用ＳＤＳ裂解缓冲液提取斜纹夜蛾幼虫中肠组织细胞总蛋白。采用病毒铺覆蛋白印迹技术（ＶＯＰＢＡ）,利用抗ＰＶＤ抗血清对病毒受体进行检测,结果表明斜纹夜蛾中肠细胞总蛋白中４０ｋＤ、７３ｋＤ、８５ｋＤ的三种蛋白能够结合ＰＤＶ。     

逆转录-聚合酶链式反应技术检测"歇马杏"主要病毒

目的：调查“歇马杏”携带主要病毒的情况。方法：利用作者已建立的ACLSV、PNRSV和PDVRT—PCR检测体系对4宁省大连市地方特产“歇马杏”田间植株携带三种病毒的情况进行了调查。结果：被检植株ACLSV、PNRSV和PDV的单独感染率分别为83．33％、83．33％和190％,复合感染率达到76．67％,但带毒程度不同。     

Arabidopsis FtsZ2-1 and FtsZ2-2 Are Functionally Redundant,But FtsZ-Based Plastid Division Is Not Essential for Chloroplast Partitioning or Plant Growth and Development

FtsZ1 and FtsZ2 are phylogenetically distinct families of FtsZ in plants that co-localize to mid-plastid rings and facilitate division of chloroplasts. In plants, altered levels of either FtsZ1 or FtsZ2 cause dose-dependent defects in chloroplast division; thus, studies on the functional relationship between FtsZgenes require careful manipulation of FtsZ levels in vivo. To define the functional relationship between the two FtsZ2 genes in Arabidopsis thaliana, FtsZ2-1 and FtsZ2-2, we expressed FtsZ2-1 in an ftsZ2-2 null mutant, and vice versa, and determined whether the chloroplast division defects were rescued in plants expressing different total levels of FtsZ2. Full rescue was observed when either the FtsZ2-1 or FtsZ2-2 level approximated total FtsZ2 levels in wild-type （WT）. Additionally, FtsZ2-2 interacts with ARC6, as shown previously for FtsZ2- 1. These data indicate that FtsZ2-1 and FtsZ2-2 are functionally redundant for chloroplast division in Arabidopsis. To rigorously validate the requirement of each FtsZ family for chloroplast division, we replaced FtsZ1 with FtsZ2 in vivo, and vice versa, while maintaining the FtsZ level in the transgenic plants equal to that of the total level in WT. Chloroplast division defects were not rescued, demonstrating conclusively that FtsZ1 and FtsZ2 are non-redundant for maintenance of WT chloroplast numbers. Finally, we generated ftsZtriple null mutants and show that plants completely devoid of FtsZ protein are viable and fertile. As plastids are presumably essential organelles, these findings suggest that an FtsZ-independent mode of plastid partitioning may occur in higher plants.