MHP1 and MHL generate odd-chain fatty acids from 2-hydroxy fatty acids in sphingolipids and are related to immunity in Arabidopsis thaliana

Marina Ushio; Toshiki Ishikawa; Takakazu Matsuura; Izumi C Mori; Maki Kawai-Yamada; Yoichiro Fukao; Minoru Nagano

doi:10.1016/j.plantsci.2023.111840

MHP1 and MHL generate odd-chain fatty acids from 2-hydroxy fatty acids in sphingolipids and are related to immunity in Arabidopsis thaliana

Plant Sci. 2023 Nov:336:111840. doi: 10.1016/j.plantsci.2023.111840. Epub 2023 Aug 22.

Authors

Marina Ushio¹, Toshiki Ishikawa², Takakazu Matsuura³, Izumi C Mori³, Maki Kawai-Yamada², Yoichiro Fukao⁴, Minoru Nagano⁵

Affiliations

¹ Graduate School of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan.
² Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakuraku, Saitama 338-8570, Japan.
³ Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan.
⁴ Graduate School of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan; College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan.
⁵ College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan. Electronic address: mnagano@fc.ritsumei.ac.jp.

PMID: 37619867
DOI: 10.1016/j.plantsci.2023.111840

Abstract

In plants, the 2-hydroxy fatty acids (HFAs) of sphingolipids are important for plant growth and stress responses. Although the synthetic pathway of HFAs is well understood, their degradation has not yet been elucidated. In Saccharomyces cerevisiae, Mpo1 has been identified as a dioxygenase that degrades HFAs. This study examined the functions of two homologs of yeast Mpo1, MHP1 and MHL, in Arabidopsis thaliana. The mhp1 and mhp1mhl mutants showed a dwarf phenotype compared to that of the wild type. Lipid analysis of the mutants revealed the involvement of MHP1 and MHL in synthesizing odd-chain fatty acids (OCFAs), possibly by the degradation of HFAs. OCFAs are present in trace amounts in plants; however, their physiological significance is largely unknown. RNA sequence analysis of the mhp1mhl mutant revealed that growth-related genes decreased, whereas genes involved in stress response increased. Additionally, the mhp1mhl mutant had increased expression of defense-related genes and increased resistance to infection by Pseudomonas syringae pv. tomato DC3000 (Pto), and Pto carrying the effector AvrRpt2. Phytohormone analysis demonstrated that jasmonic acid in mhp1mhl was higher than that in the wild type. These results indicate that MHP1 and MHL are involved in synthesizing OCFAs and immunity in Arabidopsis.

Keywords: 2-hydroxy fatty acids; Disease resistance; Jasmonic acid; Mpo1; Odd-chain fatty acids; Sphingolipids.