GhATL68b regulates cotton fiber cell development by ubiquitinating the enzyme required for β-oxidation of polyunsaturated fatty acids  

作　　者：Xin Li Gai Huang Yifan Zhou Kun Wang Yuxian Zhu 

机构地区：[1]College of Life Sciences,Wuhan University,Wuhan 430072,China [2]Institute for Advanced Studies,Wuhan University,Wuhan 430072,China [3]Hubei Hongshan Laboratory,Wuhan 430072,China [4]TaiKang Center for Life and Medical Sciences,Wuhan University,Wuhan 430072,China [5]State Key Laboratory of Plant Genomics and National Center for Plant Gene Research,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,Beijing 100101,China

出　　处：《Plant Communications》2024年第10期139-153,共15页植物通讯（英文）

基　　金：supported by the National Natural Science Foundation of China(31830057);the National Key R&D Program of China(2022YFF1001400);the Foundation of Hubei Hongshan Laboratory(2021hszd014).

摘　　要：E3 ligases are key enzymes required for protein degradation.Here,we identified a C3H2C3 RING domaincontaining E3 ubiquitin ligase gene named GhATL68b.It is preferentially and highly expressed in developing cotton fiber cells and shows greater conservation in plants than in animals or archaea.The four orthologous copies of this gene in various diploid cottons and eight in the allotetraploid G.hirsutum were found to have originated from a single common ancestor that can be traced back to Chlamydomonas reinhardtii at about 992 million years ago.Structural variations in the GhATL68b promoter regions of G.hirsutum,G.herbaceum,G.arboreum,and G.raimondii are correlated with significantly different methylation patterns.Homozygous CRISPR-Cas9 knockout cotton lines exhibit significant reductions in fiber quality traits,including upper-half mean length,elongation at break,uniformity,and mature fiber weight.In vitro ubiquitination and cell-free protein degradation assays revealed that GhATL68b modulates the homeostasis of 2,4-dienoyl-CoA reductase,a rate-limiting enzyme for theβ-oxidation of polyunsaturated fatty acids(PUFAs),via the ubiquitin proteasome pathway.Fiber cells harvested from these knockout mutants contain significantly lower levels of PUFAs important for production of glycerophospholipids and regulation of plasma membrane fluidity.The fiber growth defects of the mutant can be fully rescued by the addition of linolenic acid(C18:3),the most abundant type of PUFA,to the ovule culture medium.This experimentally characterized C3H2C3 type E3 ubiquitin ligase involved in regulating fiber cell elongation may provide us with a new genetic target for improved cotton lint production.

关 键 词：Gossypium hirsutum E3 ligases polyunsaturated fatty acids β-oxidation fiber development 

分 类 号：Q94[生物学—植物学]