Analysis of a tetraploid cotton line Mac7 transcriptome reveals mechanisms underlying resistance against the whitefly Bemisia tabaci

Authors: ASLAM, MUHAMMAD - National Institute Of Biotechnology And Genetic Engineering (NIBGE); NAQVI, RUBAB - National Institute Of Biotechnology And Genetic Engineering (NIBGE); ASIF, MUHAMMAD - National Institute Of Biotechnology And Genetic Engineering (NIBGE); AKHTER, KHALID - National Institute Of Biotechnology And Genetic Engineering (NIBGE); Scheffler, Brian; Scheffler, Jodi; LIU, SHU-SHENG - National Institute Of Biotechnology And Genetic Engineering (NIBGE); AMIN, IMRAN - National Institute Of Biotechnology And Genetic Engineering (NIBGE); MANSOOR, SHAHID - National Institute Of Biotechnology And Genetic Engineering (NIBGE)

Submitted to: Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2022
Publication Date: 2/4/2022
Publication URL: https://handle.nal.usda.gov/10113/7663843
Citation: Aslam, M.Q., Naqvi, R.Z., Asif, M., Akhter, K.P., Scheffler, B.E., Scheffler, J.A., Liu, S., Amin, I., Mansoor, S. 2022. Analysis of a tetraploid cotton line Mac7 transcriptome reveals mechanisms underlying resistance against the whitefly Bemisia tabaci. Gene. 820:146200. https://doi.org/10.1016/j.gene.2022.146200.
DOI: https://doi.org/10.1016/j.gene.2022.146200

Interpretive Summary: Cultivated cotton (Gossypium hirsutum) is an economically important crop that can be severely damaged by whitefly (Bemisia tabaci) attack (infestation). A cotton experimental line Mac7 (GVS9) released by the United States Department of Agriculture (USDA) cotton breeding program at Stoneville, MS was identified with tolerance to whiteflies. This study used special molecular techniques to study the changes in gene expression in Mac7 plants when they were infested with whiteflies versus an uninfested plant or a susceptible cotton variety. The study identified genes that increased in expression in the infested plants, but not in the uninfested plants. These genes are known to code for proteins that protect the plant from pest invasion. There were also genes that did not increase in expression in the infested Mac7 plants, but did in the susceptible variety. Some of these genes are known to encode plant proteins that pests, such as whiteflies, highjack to help them more easily attack the plant. This information will help understand the mechanism of tolerance in Mac7 and lead to strategies to improve tolerance and resistance in susceptible cultivated cotton.

Technical Abstract: Due to its unique fiber yield and oil-producing qualities, cotton is among the most widely cultivated cash crops in the world. Nonetheless, cotton production is significantly reduced due to whitefly attacks. Whitefly inflicts both direct and indirect losses to the cotton crop. Identifying whitefly resistant cotton germplasm is a high priority and considered among the best possible solutions to mitigate the whitefly problem. In the present study, we evaluated the CLCuD resistant cotton line Mac7 under whitefly stress and revealed its potential as a source of resistance against the Asia II1 species of Bemisia tabaci, prevalent in Punjab, Pakistan. Furthermore, we utilized the already available transcriptome data from Mac7 with reference to whitefly stress to elucidate associated mechanisms and identify functionally important genes in cotton. In the transcriptomic data, differentially expressed genes were found which were involved in complex relay pathways in Mac7 activated on attack by whiteflies. The response implicates signaling through R-genes, MAPK, ROS, VQs or RLKs and transcription factors, which leads to switching on of defense responses including, Ca+ messengers, phytohormonal cross-talk, gossypol, flavonoids, PhasiRNA and S-genes. qRT-PCR of ten functionally important genes was performed and showed their involvement in differential responses at 24 and 48 hours after whitefly infestation. In a nutshell, our study portrays an inclusive insight into defense responses of Mac7 cotton to whitefly and pinpoints putative functionally important insect resistance genes in cotton.