The calcium sensor GhCaM7 promotes cotton fiber elongation by modulating reactive oxygen species (ROS) production

Abstract

SummaryFiber elongation is the key determinant of fiber quality and output in cotton (Gossypium hirsutum). Although expression profiling and functional genomics provide some data, the mechanism of fiber development is still not well understood.Here, a gene encoding a calcium sensor, GhCaM7, was isolated based on its high expression level relative to other GhCaMs in fiber cells at the fast elongation stage. The level of expression of GhCaM7 in the wild-type and the fuzzless/lintless mutant correspond to the presence and absence, respectively, of fiber initials.Overexpressing GhCaM7 promotes early fiber elongation, whereas GhCaM7 suppression by RNAi delays fiber initiation and inhibits fiber elongation. Reactive oxygen species (ROS) play important roles in early fiber development. ROS induced by exogenous hydrogen peroxide (H 2 O 2 ) and Ca 2+ starvation promotes early fiber elongation. GhCaM7 overexpression fiber cells show increased ROS concentrations compared with the wild-type, while GhCaM7 RNAi fiber cells have reduced concentrations. Furthermore, we show that H 2 O 2 enhances Ca 2+ influx into the fiber and feedback-regulates the expression of GhCaM7. We conclude that GhCaM7, Ca 2+ and ROS are three important regulators involved in early fiber elongation. GhCaM7 might modulate ROS production and act as a molecular link between Ca 2+ and ROS signal pathways in early fiber development.

A high-efficiency CRISPR/Cas9 system for targeted mutagenesis in Cotton (Gossypium hirsutum L.)

“…However, the complex genome feature of allotetraploid cotton presents a new challenge for cotton genes functional analyses and the genetic improvement through transgenic approach. Previously, many cotton genes were identified to be implicated in cotton fibre development45678910111213141516, stress responsees17181920, and pathogen immune regulation through expressed sequence tag (EST)-based cDNA library coupled with conventional RNAi and gene overexpression strategies21222324. With the rapid development of high throughput deep sequencing technologies and bioinformatics, many diploid and allotetraploid cotton species were sequenced and assembled within recent years, including D-genome diploids cotton Gossypium raimondii (DD; 2n = 26)2526, A-genome diploids Gossypium arboreum (AA; 2n = 26)27, ant the AtDt allotetraploid cotton species Gossypium hirsutum and Gossypium barbadense 282930.…”

A Cotton Annexin Affects Fiber Elongation and Secondary Cell Wall Biosynthesis Associated with Ca2+ Influx, ROS Homeostasis, and Actin Filament Reorganization

“…A significant ROS burst occurs at the time of fiber initiation and early elongation, and when ROS production was inhibited by the NADPH oxidase inhibitor diphenylene iodonium (DPI) or the peroxidase inhibitor salicylhydroxamic acid, fiber elongation was suppressed (Mei et al, 2009). Recently, researchers also proved that Ca 2+ and ROS play pivotal roles in fiber elongation in cotton through the gain and loss of function of GhCaM7 (Tang et al, 2014b). In addition to Ca 2+ and ROS, actin filaments are essential for fiber elongation.…”

Transgenic Bt cotton driven by the green tissue-specific promoter shows strong toxicity to lepidopteran pests and lower Bt toxin accumulation in seeds

“…For this purpose, two cotton cultivars YZ-1 and Y668 were successfully transformed with the PNZIP::GUS and PNZIP::Cry9C genes, respectively. YZ-1 is an elite cotton cultivar identified in 2006 (Jin et al, 2006) and widely used in cotton genetic transformation (Deng et al, 2012;Tang et al, 2014) for its superior transformation efficiency and shorter regeneration periods in comparison to Coker lines. Y668 is a recently identified elite cotton cultivar with comparable regenerability as that of YZ-1, and superior agronomic traits.…”