|UKWATTA, JAYAN - Texas Tech University
|PABUAYON, ISAIAH CATALINO - Texas Tech University
|PARK, JUNGJAE - Texas Tech University
|CHAI, XIAOQIANG - Chinese Academy Of Sciences
|ZHANG, HENG - Chinese Academy Of Sciences
|ZHU, JIAN-KANG - Chinese Academy Of Sciences
|SHI, HUAZHONG - Texas Tech University
Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2021
Publication Date: 10/16/2021
Citation: Ukwatta, J., Pabuayon, I.M., Park, J., Chen, J., Chai, X., Zhang, H., Zhu, J., Xin, Z., Shi, H. 2021. Comparative physiological and transcriptomic analysis reveals salt tolerance mechanisms in Sorghum bicolor (L.) Moench. Planta. 254(98). https://doi.org/10.1007/s00425-021-03750-w.
Interpretive Summary: Sorghum is an annual tropical C4 grass and one of the first domesticated cereal crops. It is grown across a wide range of environments and serves as an important source of food, fodder, fiber, fuel, and building materials. Sorghum is known for its excellent tolerance to high temperature and drought but moderate tolerance to salt stress. In this study, we have identified a Nigerien landrace, Mota Maradi, which possesses excellent tolerance to salt stress. Mechanisms of salt tolerance were identified by comparison the gene expression and metabolite profiles between this landrace and an inbred line BTx623, which has been used to generate the sorghum reference genome sequence. This study highlights the unique adaptation of landraces towards their respective ecosystems, and their strong potential as genetic resources for future plant breeding endeavors.
Technical Abstract: High soil salinity is one of the global challenges for crop growth and productivity. Understanding the salt tolerance mechanisms in crops is necessary for genetic breeding of salt tolerant crops. In this study, physiological and molecular mechanisms in sorghum were identified through a comparative analysis between a Nigerien salt-tolerant sorghum landrace, Mota Maradi, and the reference sorghum line, BTx623. Significant differences on physiological performances were observed, particularly on growth and biomass gain, photosynthetic rate, and the accumulation of Na+, K+, proline, and sucrose. Transcriptome profiling of the leaves, leaf sheaths, stems, and roots revealed contrasting differentially expressed genes (DEGs) in Mota Maradi and BTx623 which supports the physiological observations from both lines. Among the DEGs, ion transporters such as HKT, NHX, AKT, HAK5, and KUP3 were likely to be responsible for the differences in Na+ and K+ accumulation. Meanwhile, DEGs involved in photosynthesis, cellular growth, signaling, and ROS scavenging were also identified between these two genotypes. Functional and pathway analysis of the DEGs has revealed that these processes work in concert and are crucial in elevated salt tolerance in Mota Maradi. Our findings indicate how different complex processes work synergistically for salt stress tolerance in sorghum. This study also highlights the unique adaptation of landraces towards their respective ecosystems, and their strong potential as genetic resources for future plant breeding endeavors.