Identification and functional characterization of a leucine-rich repeat receptor-like kinase gene that is involved in regulation of soybean leaf senescence
Identification and functional characterization of a leucine-rich repeat receptor-like kinase gene that is involved in regulation of soybean leaf senescence
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参与大豆叶片衰老调节的富含亮氨酸重复受体样激酶基因的鉴定和功能表征
DOI：
10.1007/s11103-006-0052-5
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发表时间：
2006-08-01
影响因子：
5.1
通讯作者：
Wang, Ning Ning
中科院分区：
文献类型：
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作者：
Li, Xiao-Ping;Gan, Rui;Wang, Ning Ning
我们在这里报告的大豆受体样激酶（RLK）基因的克隆和鉴定，指定GmSARK（大豆衰老相关受体样激酶），这是参与调节叶片衰老。GmSARK的概念性蛋白产物包含LRR受体样激酶的典型结构域：具有所有11个激酶亚结构域的胞质结构域、跨膜结构域和含有9个富含亮氨酸重复（LRR）单元的细胞外结构域，其可以充当受体。GmSARK基因在大豆叶片衰老过程中的表达在子叶衰老、暗诱导初生叶衰老和开花后自然衰老过程中均呈上调趋势。此外，RNA干扰（RNAi）介导的敲低GmSARK显着延缓大豆叶片衰老。GmSARK-RNAi转基因植株的类囊体膜系统更为复杂，叶片叶绿素含量更高，叶绿体结构的衰老诱导解体也得到了非常显著的延缓。玉米致死叶斑病1基因的一个同源基因已被分离并命名为Gmlls 1，该基因被认为编码催化叶绿素分解的关键酶。同时对叶绿素合成关键酶Gmgtr 1基因的表达水平进行了分析。结果表明，在野生型大豆叶片衰老过程中，Gmlls 1表达上调，Gmgtr 1表达下调。而GmSARK-RNAi转基因叶片衰老过程中Gmlls 1的上调和Gmgtr 1的下调均受到抑制。此外，过量表达GmSARK基因大大加速了CaMV 35 S：GmSARK转基因植株的衰老进程。综上所述，这些结果有力地表明，该LRR-RLK参与调节大豆叶片衰老，可能通过调节叶绿体发育和叶绿素积累。本文还讨论了GmSARK除调控叶片衰老外的多种功能。
We report here the cloning and characterization of a soybean receptor-like kinase (RLK) gene, designated GmSARK (Glycine max senescence-associated receptor-like kinase), which is involved in regulating leaf senescence. The conceptual protein product of GmSARK contains typical domains of LRR receptor-like kinases: a cytoplasmic domain with all the 11 kinase subdomains, a transmembrane domain and an extracelullar domain containing 9 Leucine-Rich Repeat (LRR) units that may act as a receptor. The expression of GmSARK in soybean leaves was up-regulated in all the three tested senescence systems: senescing cotyledons, dark-induced primary leaf senescence and the natural leaf senescence process after florescence. Furthermore, the RNA interference (RNAi)-mediated knocking-down of GmSARK dramatically retarded soybean leaf senescence. A more complex thylakoid membrane system, higher foliar level of chlorophyll content and a very remarkable delay of senescence-induced disintegration of chloroplast structure were observed in GmSARK-RNAi transgenic leaves. A homolog of maize lethal leaf-spot 1 gene, which has been suggested to encode a key enzyme catalyzing chlorophyll breakdown, was isolated and nominated Gmlls1. The expression level of Gmgtr1 gene, which encodes a key enzyme of chlorophyll synthesis, was also analyzed. It was found that Gmlls1 was up-regulated and Gmgtr1 was down-regulated during senescence in wild-type soybean leaves. However, both of the up-regulation of Gmlls1 and down-regulation of Gmgtr1 were retarded during senescence of GmSARK-RNAi transgenic leaves. In addition, over-expression of the GmSARK gene greatly accelerated the senescence progression of CaMV 35S:GmSARK transgenic plants. Taken together, these results strongly suggested the involvement of this LRR-RLK in regulation of soybean leaf senescence, maybe via regulating chloroplast development and chlorophyll accumulation. Multiple functions of GmSARK besides its regulation of leaf senescence were also discussed.