Regulation and physiological function of proteins for heat tolerance in cowpea (Vigna unguiculata) genotypes under controlled and field conditions

Tonny I Selinga; Sipho T Maseko; Hawwa Gabier; Mohammed S Rafudeen; A Muthama Muasya; Olivier Crespo; John B O Ogola; Alex J Valentine; Carl-Otto Ottosen; Eva Rosenqvist; Samson B M Chimphango

doi:10.3389/fpls.2022.954527

Regulation and physiological function of proteins for heat tolerance in cowpea (Vigna unguiculata) genotypes under controlled and field conditions

Front Plant Sci. 2022 Aug 22:13:954527. doi: 10.3389/fpls.2022.954527. eCollection 2022.

Affiliations

¹ Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa.
² Department of Crop Sciences, Tshwane University of Technology, Pretoria, South Africa.
³ Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa.
⁴ Climate System Analysis Group, Department of Environmental and Geographical Science, University of Cape Town, Rondebosch, South Africa.
⁵ Department of Plant and Soil Sciences, University of Venda, Thohoyandou, South Africa.
⁶ Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa.
⁷ Department of Food Science, Aarhus University, Aarslev, Denmark.
⁸ Section for Crop Science, Department of Plant and Environmental Sciences, University of Copenhagen, Taastrup, Denmark.

Abstract

The expression of heat shock proteins is considered a central adaptive mechanism to heat stress. This study investigated the expression of heat shock proteins (HSPs) and other stress-protective proteins against heat stress in cowpea genotypes under field (IT-96D-610 and IT-16) and controlled (IT-96D-610) conditions. Heat stress response analysis of proteins at 72 h in the controlled environment showed 270 differentially regulated proteins identified using label-free quantitative proteomics in IT-96D-610 plants. These plants expressed HSPs and chaperones [BAG family molecular chaperone 6 (BAG6), Multiprotein bridging factor1c (MBF1C) and cold shock domain protein 1 (CSDP1) in the controlled environment]. However, IT-96D-610 plants expressed a wider variety of small HSPs and more HSPs in the field. IT-96D-610 plants also responded to heat stress by exclusively expressing chaperones [DnaJ chaperones, universal stress protein and heat shock binding protein (HSBP)] and non-HSP proteins (Deg1, EGY3, ROS protective proteins, temperature-induced lipocalin and succinic dehydrogenase). Photosynthesis recovery and induction of proteins related to photosynthesis were better in IT-96D-610 because of the concurrent induction of heat stress response proteins for chaperone functions, protein degradation for repair and ROS scavenging proteins and PSII operating efficiency (Fq'/Fm') than IT-16. This study contributes to identification of thermotolerance mechanisms in cowpea that can be useful in knowledge-based crop improvement.

Keywords: cowpea; heat shock proteins; label-free protein quantification; plant proteomics; thermotolerance mechanisms.