Pumpkin (Cucurbita moschata) HSP20 Gene Family Identification and Expression Under Heat Stress.

Yanping Hu,Min Wang,Yang Zhou,Ying Liu,Tianhai Yun,Yuxin Li,Baibi Zhu,Daolong Liao,Wenfeng Huang,Wen Zhang,Tingting Zhang

doi:10.3389/fgene.2021.753953

Abstract

Pumpkin (Cucurbita moschata) is an important cucurbit vegetable crop that has strong resistance to abiotic stress. While heat shock protein 20 (HSP20) has been implicated in vegetable response to heat stress, little is known regarding activity of HSP20 family proteins in C. moschata. Here, we performed a comprehensive genome-wide analysis to identify and characterize the functional dynamics of the Cucurbita moschata HSP20 (CmoHSP20) gene family. A total of 33 HSP20 genes distributed across 13 chromosomes were identified from the pumpkin genome. Our phylogenetic analysis determined that the CmoHSP20 proteins fell into nine distinct subfamilies, a division supported by the conserved motif composition and gene structure analyses. Segmental duplication events were shown to play a key role in expansion of the CmoHSP20 gene family. Synteny analysis revealed that 19 and 18 CmoHSP20 genes were collinear with those in the cucumber and melon genomes, respectively. Furthermore, the expression levels of pumpkin HSP20 genes were differentially induced by heat stress. The transcript level of CmoHSP20-16, 24 and 25 were down-regulated by heat stress, while CmoHSP20-7, 13, 18, 22, 26 and 32 were up-regulated by heat stress, which could be used as heat tolerance candidate genes. Overall, these findings contribute to our understanding of vegetable HSP20 family genes and provide valuable information that can be used to breed heat stress resistance in cucurbit vegetable crops.

Highlights

Plants are typically afflicted by a wide variety of abiotic and biotic stresses during growth, including as extreme heat, cold, drought, elevated salinity levels, and pest and pathogen infestations
CmoHSP20 genes were distributed on 13 pumpkin chromosomes
We found that the number of pumpkin heat shock protein 20 (HSP20) genes was similar to those in Arabidopsis (N 31) and O. sativa (N 33), as well as Capsicum annuum (N 35) (Guo et al, 2015), but lower than that of Gossypium hirsutum (N 94) (Ma et al, 2016)

Summary

Introduction

Plants are typically afflicted by a wide variety of abiotic and biotic stresses during growth, including as extreme heat, cold, drought, elevated salinity levels, and pest and pathogen infestations. Heat shock protein (HSP) are often associated with plant responses to temperature stress, heavy metals and reactive oxygen species (ROS) (Sun et al, 2002), as well as infection by pathogens (Maimbo et al, 2007; Sarkar et al, 2009; Kandoth et al, 2011). Extreme temperatures can Analysis of CmoHSP20s in C. moschata reduce seed vigor, inhibit germination, and restrict plant growth (Yamori et al, 2014). It is important, to understand the plant heat tolerance. HSP produced under high temperature stress is highly conservative proteins in organisms (Gupta et al, 2010). The abundance of heat shock proteins is typically low under normal conditions, but under heat stress, rapidly grows to account for up to 15% of the total protein content in organisms (Swindell et al, 2007)

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Discussion

Conclusion