Proteomic analysis reveals different responses to drought between the Cleome spinosa (C3) and Cleome gynandra (C4)

Abstract

The global emergence of low water availability causes extensive damage to crops in many regions. Although the responses of plants to drought stress have been extensively investigated, molecular studies on plants with different carboxylation pathways are limited. Therefore, we aimed to identify quantitative differences in proteins functioning in differential drought tolerance of C3 (Cleome spinosa) and C4 (C. gynandra) species. Proteomic analysis functionally characterized 33 differentially accumulated proteins in C. spinosa and 15 proteins in C. gynandra leaves. The identified proteins were involved in multiple aspects of leaf metabolism such as photosynthesis, energy metabolism, protein metabolism, and stress defense. The up-regulated accumulation of RuBisCO proteins may have contributed to carboxylation in stressed C. spinosa, but RuBisCO activase proteins were severely down-regulated. Additionally, down-regulation of ferredoxin-nicotinamide adenine dinucleotide phosphate (NADP) reductase and oxygen-evolving enhancer proteins was only found in C. spinosa, which possibly related to the inhibition of electron flow. The up-regulation of enolase may contribute to the energy requirement in C. gynandra, while down-regulation of glycolytic enzymes, such as fructose-bisphosphate aldolase and triosephosphate isomerase, was found in C. spinosa suggesting the impaired energy metabolism under drought stress. The proteomic analysis suggests different adaptive strategies between C. spinosa and C. gynandra against drought stress.