文献类型：期刊文献

英文题名：SaRac1, a small GTPase, plays an essential role in haustorium development in the root parasite sandalwood (Santalum album)

作者：Meng, Sen[1,2,3] Bian, Zhan[4] Wang, Shengkun[1] Qin, Fangcuo[1] Wang, Dongli[1] Chen, Yu[3] Lu, Junkun[1]

第一作者：孟森;Meng, Sen

通信作者：Lu, JK[1]

机构：[1]Chinese Acad Forestry, Res Inst Trop Forestry, State Key Lab Tree Genet & Breeding, 682 Guangshan 1st Rd, Guangzhou 510520, Guangdong, Peoples R China;[2]Salver Acad Bot, 95 Lanling Rd, Rizhao 262300, Shandong, Peoples R China;[3]Chongqing Three Gorges Univ, Coll Biol & Food Engn, 666 Tianxing Rd, Chongqing 404100, Peoples R China;[4]Chinese Acad Sci, Guangdong Prov Key Lab Appl Bot, South China Bot Garden, 723 Xingke Rd, Guangzhou 510650, Guangdong, Peoples R China

年份：2025

卷号：45

期号：12

外文期刊名：TREE PHYSIOLOGY

收录：;Scopus(收录号：2-s2.0-105025677615);WOS:【SCI-EXPANDED(收录号:WOS:001643960900001)】；

基金：This research was supported by grants from the National Key R&D Program of China (2022YFD2202000), the National Natural Science Foundation of China (31722012, 31901304 and 32401636), Guangdong Basic and Applied Basic Research Foundation (2023A1515012709 and 2025A1515010797) and Science and Technology Projects in Guangzhou (2024A04J4740).

语种：英文

外文关键词：gene silence; parasitic plant; Rac protein; ROS; SaRbohA

摘要：Indian sandalwood (Santalum album) is an economically important facultative parasite that develops a specialized multicellular organ, the haustorium, to absorb water and nutrients from its hosts. To elucidate the molecular mechanisms underlying haustorium development, we conducted a transcriptome analysis across six S. album tissues. We found that SaRac1, encoding a functional small GTPase, is specifically expressed in the haustorium. We employed host-induced gene silencing (HIGS) by generating transgenic poplar (Populus alba x P. glandulosa) hosts that express hairpin RNAs to target and downregulate SaRac1 in the parasite. Santalum album grown with SaRac1 RNAi transgenic host plants exhibited significantly suppressed haustorium development compared with those grown with wild-type or empty-vector controls. Mechanistically, SaRac1 interacts with SaRbohA, and this interaction synergistically enhances ROS production. Exogenous H2O2 application significantly upregulated key haustorium formation-related genes. In contrast, the Rboh inhibitor diphenyliodonium chloride (DPI) suppressed the expression of SaYUCCA and SaSBT in S. album grown with wild-type and empty-vector control hosts, thereby reducing haustorium formation. In S. album plants grown with RNAi hosts, SaSBT and SaEXPA were also downregulated by DPI application. Our findings identify a crucial mechanism whereby SaRac1 promotes haustorium formation by modulating ROS signaling and provide novel insights into the molecular physiology of plant parasitism.