Programmed cell death during flower senescence:: isolation and characterization of cysteine proteinases from Sandersonia aurantiaca
Programmed cell death during flower senescence:: isolation and characterization of cysteine proteinases from Sandersonia aurantiaca
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DOI：
10.1071/pp01174
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发表时间：
2002-01-01
影响因子：
3
通讯作者：
O'Donoghue, EM
中科院分区：
文献类型：
--
作者：
Eason, JR;Ryan, DJ;O'Donoghue, EM
半胱氨酸蛋白酶抑制剂可延缓桑白皮的衰老。花花被褪色和萎蔫发生在2，2 '-联吡啶处理的花中，并且与保持在水中的对照花相比，这些花具有更大的可溶性蛋白质含量和更少的活性内切蛋白酶。生化分析表明，存在的几个蛋白酶活性条带中的可溶性蛋白组分的Sandersonia花被片。随着花衰老的进行，多肽的活性增加。Western分析与蓖麻半胱氨酸蛋白酶的抗体提出了确定同源蛋白质Sandersonia花（约46，41和31 kDa）。从Sandersonia花被片中分离到三个编码半胱氨酸蛋白酶的cDNA（PRT 5、PRT 15和PRT 22）。这三个表达增加花被片衰老的进展。PRT 5的mRNA仅在衰老的花组织中检测到，而PRT 15和PRT 22在叶、茎和根组织中表达。PRT 5与C-末端KDEL蛋白具有显著的同源性，其在程序性细胞死亡期间在植物细胞内容物的降解中起作用。PRT 15与具有长C-末端延伸的半胱氨酸蛋白酶最相似，而PRT 22与应激诱导的半胱氨酸蛋白酶同源。
Cysteine protease inhibitors delayed the senescence of Sandersonia aurantiaca Hook. flowers. Tepal fading and wilting occurred later in the 2,2'-dipyridyl-treated flowers, and these flowers had a greater soluble protein content and less active endoproteases compared with control flowers that were held in water. Biochemical analysis revealed the presence of several protease-active bands in the soluble protein fraction of Sandersonia tepals. Activity of the polypeptides increased as flower senescence progressed. Western analysis with an antibody raised against the castor bean cysteine proteinase identified homologous proteins in Sandersonia flowers (ca 46, 41 and 31 kDa). Three cDNAs encoding cysteine proteinases were isolated from Sandersonia tepals (PRT5, PRT15 and PRT22). Expression of all three increased in tepals as senescence progressed. mRNAs for PRT5 were detected only in senescing flower tissue, whereas PRT15 and PRT22 were expressed in leaf, stem and root tissue. PRT5 has significant homology to C-terminus KDEL proteins, which have a role in the degradation of plant cell contents during programmed cell death. PRT15 is most similar to cysteine proteinases with a long C-terminal extension, whereas PRT22 is homologous to stress-induced cysteine proteinases.