Genome-Wide Identification and Functional Investigation of 1-Aminocyclopropane-1-carboxylic Acid Oxidase (ACO) Genes in Cotton.

Hengling Wei,Pengyun Chen,Lu Sun,Yonglin Yang,Pengbo Hao,Fei Wei,Yujun Xue

doi:10.3390/plants10081699

Hengling Wei, Pengyun Chen + Show 5 more

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https://doi.org/10.3390/plants10081699

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Abstract

ACO is one of the rate-limiting enzymes in the biosynthesis of ethylene, and it plays a critical role in the regulation of plant growth and development. However, the function of ACO genes in cotton is not well studied. In this study, a total of 332 GhACOs, 187 GaACOs, and 181 GrACOs were identified in G. hirsutum, G. arboretum, and G. raimondii, respectively. Gene duplication analysis showed that whole-genome duplication (WGD) and tandem duplication were the major forces driving the generation of cotton ACO genes. In the promoters of GhACOs, there were cis-acting elements responding to stress, phytohormones, light, and circadian factors, indicating the possible involvement of GhACOs in these processes. Expression and co-expression analyses illustrated that most GhACOs were not only widely expressed in various tissues but also coexpressed with other genes in response to salt and drought stress. GhACO106_At overexpression in Arabidopsis promoted flowering and increased salt tolerance. These results provide a comprehensive overview of the ACO genes of cotton and lay the foundation for subsequent functional studies of these genes.

Highlights

Ethylene has a variety of physiological regulatory functions throughout the life of plants, including roles in flower formation, fruit maturation, and senescence [1,2,3,4]
332 GhACOs, 187 GaACOs, and 181 GrACOs were identified from G. hirsutum (Gh), G. arboretum (Ga), and G. raimondii (Gr), respectively
The lengths of the proteins encoded by these ACO genes ranged from 191 to 979 amino acids; their molecular weights (MWs) ranged from 21,926.19 to 110,977.16; their pI values ranged from 4.64 to 9.72; and their grand average of hydropathicity (GRAVY) values ranged from −0.607 to 0.01 (−0.021)

Summary

Introduction

Ethylene has a variety of physiological regulatory functions throughout the life of plants, including roles in flower formation, fruit maturation, and senescence [1,2,3,4]. In tobacco, inhibiting the expression of an ACO-like gene leads to female sterility of transgenic plants and this functional defect can be recovered by treatment with ethylene [6]. With the exception of LeACO2, all the other five ACO genes are expressed during different stages of fruit ripening, and ACO transgenic tomato fruits are more resistant to storage and shrinkage than control fruits, showing that ACO genes are related to fruit ripening in tomato [8,9,10,11,12]. ACO gene expression can be induced during flowering, pollination, and petal senescence [17,18]

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