A Genome-Scale Analysis of the PIN Gene Family Reveals Its Functions in Cotton Fiber Development

Abstract

The PIN-FORMED (PIN) protein, the most important polar auxin transporter, plays a critical role in the distribution of auxin and controls multiple biological processes. However, characterizations and functions of this gene family have not been identified in cotton. Here, we identified the PIN family in Gossypium hirsutum, Gossypium arboreum, and Gossypium raimondii. This gene family was divided into seven subgroups. A chromosomal distribution analysis showed that GhPIN genes were evenly distributed in eight chromosomes and that the whole genome and dispersed duplications were the main duplication events for GhPIN expansion. qRT-PCR analysis showed a tissue-specific expression pattern for GhPIN. Likely due to the cis-element variations in their promoters, transcripts of PIN6 and PIN8 genes from the At (tetraploid genome orginated from G. arboreum) subgenome and PIN1a from the Dt (tetraploid genome orginated from G. raimondii) subgenome in G. hirsutum was significantly increased compared to the transcripts in the diploids. The differential regulation of these PIN genes after the polyploidization may be conducive to fiber initiation and elongation. Exogenously applied auxin polar transport inhibitor significantly suppressed fiber growth, which is consistent with the essential function of these PIN genes for regulating cotton fiber development. Furthermore, the overexpression of GhPIN1a_Dt, GhPIN6_At, and GhPIN8_At in Arabidopsis promoted the density and length of trichomes in leaves.

Identification and Expression Analysis of the PIN and AUX/LAX Gene Families in Ramie (Boehmeria nivea L. Gaud)

“…In contrast, BnPIN1b is strongly expressed in the bark. In an analysis of PIN genes in cotton, fiber elongation was observed when the expression of PIN genes was increased [77]. Further research on BnPIN1b may increase our knowledge of the molecular mechanisms underlying bast fiber development in ramie.…”

Genome-Scale Analysis of the WRI-Like Family in Gossypium and Functional Characterization of GhWRI1a Controlling Triacylglycerol Content

“…Two diploid cottons, G. arboreum (AA genome) and G. raimondii (DD genome), evolved from a common ancestor ( Zhang et al, 2017 ). The most widely cultivated tetraploid cotton species are G. hirsutum (AADD, AD1 genome) and G. barbadense (AADD, AD2 genome), both of which originated from inter-genomic hybridization of two A- and D-genome progenitor species ( Paterson et al, 2012 ).…”

Genome-wide identification and expression profiling of the PIN auxin transporter gene family in L. chinense

“…While studying the structure of PIN proteins, corresponding functional studies have also been carried out. As an inter-cellular auxin output protein, PIN plays an essential role in the growth and development of plants [4,9,12,20,21,26,40]. There are multiple members in most subgroups of the LcPIN gene family.…”

“…With the release of genome data for different species, the PIN gene family so far has been identi ed in a variety of living multicellular plants, such as rice, maize, cotton, soybeans, etc. [24][25][26][27]. Transcriptome data analysis and qRT-PCR showed that there might be functional interactions and redundancy between PIN genes, which also play a role in abiotic stress response and interaction with other plant hormones [27,28].…”