Transcriptome analysis reveals a comprehensive insect resistance response mechanism in cotton to infestation by the phloem feeding insect Bemisia tabaci (whitefly)

Authors: LI, JIANYING - Huazhong Agricultural University; ZHU, LIZHEN - Huazhong Agricultural University; Hull, Joe; LIANG, SIJIA - Huazhong Agricultural University; DANIELL, HENRY - University Of Pennsylvania; JIN, SHUANGXIA - Huazhong Agricultural University; ZHANG, XIANLONG - Huazhong Agricultural University

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2016
Publication Date: 3/31/2016
Citation: Li, J., Zhu, L., Hull, J.J., Liang, S., Daniell, H., Jin, S., Zhang, X. 2016. Transcriptome analysis reveals a comprehensive insect resistance response mechanism in cotton to infestation by the phloem feeding insect Bemisia tabaci (whitefly). Plant Biotechnology Journal. 14:1956-1975.

Interpretive Summary: Whiteflies are destructive pests of many plants including cotton, the predominant worldwide fiber crop. How the cotton plants defend themselves from the whitefly infestation is of extreme interest. To begin to look into this question, the sensitivity of 500 cotton cultivars to whitefly infestation was examined. The study identified two cultivars that exhibited high sensitivity and resistance respectively. The genetic expression of the two lines was further assessed at three time points after infestation. A number of differences were observed in the genetic expression between the two cultivars with many genes essential to the plant’s stress response elevated in the resistant cultivar. Genetic disruption of a subset of these genes in the resistant cotton resulted in increased levels of whitefly infestation. These results offer new insights into how cotton deal with pest infestation and provide specific avenues for future breeding programs to select for resistant cultivars.

Technical Abstract: The whitefly (Bemisia tabaci) causes tremendous damage to cotton production worldwide. However, very limited information is available about how plants perceive and defend themselves from this destructive pest. In this study, the transcriptomics differences between two cotton cultivars that exhibit either strong resistance (HR) or sensitivity (ZS) to whitefly were compared at different time points (0, 12, 24, and 48 hr after infection) using RNA-Seq. Approximately one billion paired-end reads were obtained by Illumina sequencing technology. Gene ontology and KEGG pathway analysis indicated that the cotton transcriptional response to whitefly infestation involves genes encoding protein kinases, transcription factors, metabolite synthesis, and phytohormone signaling. Further, a weighted gene co-expression network constructed from RNA-Seq datasets showed that WRKY40 and copper transport protein are hub genes that may regulate cotton defenses to whitefly infestation. Silencing GhMPK3 by virus-induced gene silencing (VIGS) resulted in suppression of the MPK-WRKY-JA and ET pathways and lead to enhanced whitefly susceptibility, suggesting that the candidate insect resistant genes identified in this RNA-Seq analysis are credible and offer significant utility. Taken together, this study provides comprehensive insights into the cotton defense system to whitefly infestation and has identified several candidate genes for control of phloem-feeding pests.