Differential gene expression patterns in Sorghum bicolor genotypes in response to high vapor pressure deficit

Authors: RAJVI, DAVE - Georgia Southern University; RODRIGUEZ, ALYSA - Georgia Southern University; Bajsa-Hirschel, Joanna; Pan, Zhiqiang - Peter; MACHINGURA, MARYLOU - Georgia Southern University

Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2021
Publication Date: 11/30/2021
Citation: Rajvi, D., Rodriguez, A., Bajsa Hirschel, J.N., Pan, Z., Machingura, M.C. 2021. Differential gene expression patterns in Sorghum bicolor genotypes in response to high vapor pressure deficit. Journal of Crop Improvement. https://doi.org/10.1080/15427528.2021.2009077.
DOI: https://doi.org/10.1080/15427528.2021.2009077

Interpretive Summary: In agriculture, drought is one of the most significant factors causing substantial loss of crop yield. Climate change escalates this weather phenomenon which has already drastically increased the size of desert areas on Earth. Some crop species (e.g., Sorghum bicolor) have developed systems protecting them from drought by simply reacting faster to changing conditions by closing or opening stomata. This mechanism is controlled by the hormone abscisic acid (ABA). In this study three drought resistant varieties of Sorghum bicolor had been tested. We analyzed the expression of genes responsible for ABA biosynthesis and measured physiological parameters such as relative water content and chlorophyll fluorescence. The increase in active ABA in sorghum shoots could be responsible for the different responses to high vapor pressure deficit.

Technical Abstract: The ability of land plants to partially close their stomata in response to high vapor pressure deficit, called the limited transpiration trait, is a rare phenomenon in crop plants. The characteristic has been demonstrated in several crop species including Sorghum bicolor, a versatile, drought-tolerant C4 grass. While the transpirational response has been shown to be under the control of the hormone abscisic acid (ABA), the regulatory mechanisms of the abscisic acid biosynthesis and translocation are not clear. In addition, different genotypes within the sorghum species respond in various ways to a change in vapor pressure deficit. In this study, three sorghum genotypes which exhibit different types of transpirational responses to high vapor pressure deficit exhibited differential gene expression patterns of ABA biosynthesis genes in response to 30 min exposure to high vapor pressure deficit. The results suggest that the natural variation in ABA content and the increase in active ABA in sorghum shoots could be responsible for the different responses to high vapor pressure deficit.