Comprehensive genome-wide analysis of the HMGR gene family of Asparagus taliensis and functional validation of AtaHMGR10 under different abiotic stresses

Liangqin Zeng Sylvia E Brown He Wu Wenhua Dongchen Yunbin Li Chun Lin Zhengjie Liu Zichao Mao ^*

• Yunnan Agricultural University, Kunming, China

3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) is a key enzyme in the terpenoid biosynthetic pathway and plays a significant role in plant stress responses. However, the HMGR gene family remains poorly understood in Asparagus taliensis, a traditional Chinese medicinal herb with higher contents of steroidal saponins as well as strong tolerance to stresses. In this study, we performed a comprehensive genome-wide analysis of the HMGR gene family in A. taliensis, identifying 18 family members and characterizing their gene structures, protein compositions, motifs, phylogenetic relationships, promoter cis-regulatory element, chromosomal localization, and collinear comparisons. Among these, AtaHMGR10 was predicted as a promising candidate due to its unique expression profile, conserved motifs for binding both HMG-CoA and NADPH/NADH with equal binding affinity to NADPH and NADH by docking analysis. Overexpression of AtaHMGR10 in transgenic Arabidopsis thaliana conferred its enhanced tolerance to abiotic stresses, as evidence with higher germination rates, improved main root length, increased levels of chlorophyll & proline, enhanced peroxidase (POD) & catalase (CAT) activities and reduced malondialdehyde (MDA) contents compared to non-transgenic plants respond to stress stimulations. These findings highlight the AtaHMGR10 function, its potential role for the synthesis of active terpenoids in microorganism hosts as well as plant stress-tolerant improvements, particularly in combating drought and salt stresses.