Genome-Wide Analysis of the Phospholipase D Family in Five Cotton Species, and Potential Role of GhPLD2 in Fiber Development and Anther Dehiscence.

Changkai Ma,Kaikai Qiao,Qifeng Ma,Qian Zhang,Jiaoyan Lv,Chaojun Zhang,Shuli Fan

doi:10.3389/fpls.2021.728025

Changkai Ma, Kaikai Qiao + Show 5 more

Open Access

https://doi.org/10.3389/fpls.2021.728025

Copy DOI

Abstract

Phospholipase D (PLD) and its hydrolysis product phosphatidic acid play an important role in the regulation of several cellular processes, including root growth, pollen tube elongation, and microtubule reorganization. Here, we systematically identified and analyzed the membership, characterization, and evolutionary relationship of PLDs in five species of cotton. The results of the transcriptomic analysis suggested that the evaluated PLD genes showed high expression levels in anther tissue and during the fiber initiation and elongation periods. Quantitative real-time polymerase chain reaction showed differential expression of GhPLD genes in the anthers of photoperiod sensitive male sterility mutant 5 (psm5). Previous research on multiple stable quantitative trait loci also suggests the role of PLD genes in the fiber development. Further analyses showed that GhPLD2 protein is localized to the plasma membrane. The virus-induced gene silencing of GhPLD2 in cotton seedlings repressed its expression by 40–70%, which led to a reduction in reactive oxygen species (ROS) levels, 22% anther indehiscence, and disrupted fiber initiation and elongation. Thus, we inferred that GhPLD2 may promote ROS production, which, in turn, may regulate anther dehiscence and fiber development.

Highlights

Cotton (Gossypium spp.) is among the most important cash crops for textiles, fine chemical raw materials, and strategically important supplies
We found that the number of Phospholipase D (PLD) genes varied among different cotton species, with 40, 40, 21, 21, and 20 genes expressed in G. hirsutum, G. barbadense, G. herbaceum, G. arboreum, and G. raimondii, respectively
Our analysis indicated that wholegenome duplication (WGD) and segmental duplication events were the main driving forces underlying PLD gene amplification and that purifying selection played a major role in the evolution of the PLD gene family

Summary

Introduction

Cotton (Gossypium spp.) is among the most important cash crops for textiles, fine chemical raw materials, and strategically important supplies. Upland cotton (G. hirsutum L.) accounts for more than 95% of cotton production owing to its excellent yield potential and adaptability. The process of cotton fiber initiation involves cell wall loosening due to increased turgor pressure in selected epidermal cells. The cotton fiber undergoes: (a) polarity elongation; (b) transitional wall thickening and primary wall remodeling; and (c) secondary wall thickening (Haigler et al, 2012). Cell division is a vital process for anther dehiscence and fiber development, and the previous evidence suggests that reactive oxygen species (ROS) homeostasis is critical for the maintenance of normal cell division in the root-tip cells of Triticum turgidum and Arabidopsis thaliana (Livanos et al, 2012b). Phospholipase D (PLD), as a an activator of ROS production, may play an important role in this process (Livanos et al, 2012a)

Methods

Results

Discussion

Conclusion