Analysis of Rac/Rop Small GTPase Family Expression in <i>Santalum album</i> L. and Their Potential Roles in Drought Stress and Hormone Treatments

Yu Chen; Shengkun Wang; Xiaojing Liu; Dongli Wang; Yunshan Liu; Lipan Hu; Sen Meng

doi:10.3390/life12121980

Life (Nov 2022)

Analysis of Rac/Rop Small GTPase Family Expression in <i>Santalum album</i> L. and Their Potential Roles in Drought Stress and Hormone Treatments

Yu Chen,
Shengkun Wang,
Xiaojing Liu,
Dongli Wang,
Yunshan Liu,
Lipan Hu,
Sen Meng

Affiliations

Yu Chen: College of Biology and Food Engineering, Chongqing Three Gorges University, Chongqing 404100, China
Shengkun Wang: State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China
Xiaojing Liu: College of Biology and Food Engineering, Chongqing Three Gorges University, Chongqing 404100, China
Dongli Wang: State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China
Yunshan Liu: College of Biology and Food Engineering, Chongqing Three Gorges University, Chongqing 404100, China
Lipan Hu: College of Biology and Food Engineering, Chongqing Three Gorges University, Chongqing 404100, China
Sen Meng: State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China

DOI: https://doi.org/10.3390/life12121980
Journal volume & issue: Vol. 12, no. 12
p. 1980

Abstract

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Plant-specific Rac/Rop small GTPases, also known as Rop, belong to the Rho subfamily. Rac proteins can be divided into two types according to their C-terminal motifs: Type I Rac proteins have a typical CaaL motif at the C-terminal, whereas type II Rac proteins lack this motif but retain a cysteine-containing element for membrane anchoring. The Rac gene family participates in diverse signal transduction events, cytoskeleton morphogenesis, reactive oxygen species (ROS) production and hormone responses in plants as molecular switches. S. album is a popular semiparasitic plant that absorbs nutrients from the host plant through the haustoria to meet its own growth and development needs. Because the whole plant has a high use value, due to the high production value of its perfume oils, it is known as the “tree of gold”. Based on the full-length transcriptome data of S. album, nine Rac gene members were named SaRac1-9, and we analyzed their physicochemical properties. Evolutionary analysis showed that SaRac1-7, AtRac1-6, AtRac9 and AtRac11 and OsRac5, OsRacB and OsRacD belong to the typical plant type I Rac/Rop protein, while SaRac8-9, AtRac7, AtRac8, AtRac10 and OsRac1-4 belong to the type II Rac/ROP protein. Tissue-specific expression analysis showed that nine genes were expressed in roots, stems, leaves and haustoria, and SaRac7/8/9 expression in stems, haustoria and roots was significantly higher than that in leaves. The expression levels of SaRac1, SaRac4 and SaRac6 in stems were very low, and the expression levels of SaRac2 and SaRac5 in roots and SaRac2/3/7 in haustoria were very high, which indicated that these genes were closely related to the formation of S. album haustoria. To further analyze the function of SaRac, nine Rac genes in sandalwood were subjected to drought stress and hormone treatments. These results establish a preliminary foundation for the regulation of growth and development in S. album by SaRac.

Published in Life

ISSN: 2075-1729 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science
Website: http://www.mdpi.com/journal/life

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