Vascular Cambium-Localized AtSPDT Mediates Xylem-to-Phloem Transfer of Phosphorus for Its Preferential Distribution in Arabidopsis  

作　　者：Guangda Ding Gui Jie Lei Naoki Yamaji Kengo Yokosho Namiki Mitani-Ueno Sheng Huang Jian Feng Ma 

机构地区：[1]institute of Plant Science and Resources,Okayama University,Chuo 2-20-1,Kurashiki,Japan [2]College of Resources and Environment,Huazhong Agricultural University,Wuhan 430070,China

出　　处：《Molecular Plant》2020年第1期99-111,共13页分子植物（英文版）

基　　金：This work was supported by a Grant-in-Aid for Specially Promoted Research(JSPS KAKENHI grant number 16H06296 to J.F.M.).

摘　　要：During plant growth and development mineral elements are preferentially delivered to different organs and tissues to meet the differential demand. It has been shown that the preferential distribution of mineral nutrients in gramineous plants is mediated by node-based transporters, but the mechanisms of preferential distribution in dicots are poorly understood. Here, we report a distinct mechanism for the preferential distribution of phosphorus (P) in Arabidopsis plants, revealed by detailed functional analysis of AtSPDT/AtSULTR3;4 (SULTR-like P Distribution Transporter), a homolog of rice OsSPDT. Like OsSPDT, AtSPDT is localized at the plasma membrane and showed proton-dependent transport activity for P. Interestingly, we found that AtSPDT is mainly expressed in the rosette basal region and leaf petiole, and its expression is up-regulated by P deficiency. Tissue-specific analysis showed that AtSPDT is mainly located in the vascular cambium of different organs, as well as in the parenchyma tissues of both xylem and phloem regions. Knockout of AtSPDT inhibited the growth of new leaves under low P due to decreased P distribution to those organs. The seed yields of the wild-type and atspdt mutant plants are similar, but the seeds of mutant plants contain – less P. These results indicate that AtSPDT localized in the vascular cambium is involved in preferential distribution of P to the developing tissues, through xylem-to-phloem transfer mainly at the rosette basal region and leaf petiole.

关 键 词：A rabidopsis THALIANA phosphate transporter SPDT PHOSPHORUS DISTRIBUTION vascular CAMBIUM 

分 类 号：Q94[生物学—植物学]