Transcriptome analysis identified coordinated control of key pathways regulating cellular physiology and metabolism upon Aspergillus flavus infection resulting in reduced aflatoxin production in groundnut

Authors: SONI, POOJA - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; NAYAK, SPURTHI - University Of Agricultural Sciences; KUMAR, RAKESH - Central University Of Karnataka; PANDEY, MANISH - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; SINGH, NAMITA - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; SUDINI, HARI - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; BAJAJ, PRASAD - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; FOUNTAIN, JAKE - Mississippi State University; SINGAM, PRASHANT - Osmania University; HONG, YANBIN - Guangdong Academy Of Agricultural Sciences; CHEN, XIAOPING - Guangdong Academy Of Agricultural Sciences; ZHUANG, WEIJIAN - Fujian Agriculture And Forest University; LIAO, BOSHOU - Chinese Academy Of Agricultural Sciences; Guo, Baozhu; VARSHNEY, RAJEEV - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India

Submitted to: The Journal of Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2020
Publication Date: 12/16/2020
Citation: Soni, P., Nayak, S.N., Kumar, R., Pandey, M.K., Singh, N., Sudini, H.K., Bajaj, P., Fountain, J.C., Singam, P., Hong, Y., Chen, X., Zhuang, W., Liao, B., Guo, B., Varshney, R.K. 2020. Transcriptome analysis identified coordinated control of key pathways regulating cellular physiology and metabolism upon Aspergillus flavus infection resulting in reduced aflatoxin production in groundnut. The Journal of Fungi. 6(4):370. https://doi.org/10.3390/jof6040370.
DOI: https://doi.org/10.3390/jof6040370

Interpretive Summary: Aspergillus flavus and A. parasiticus are two important fungi often infect peanut and produce hepatotoxic, carcinogenic, and teratogenic aflatoxins and have a significant effect on international trade and human health. Aflatoxin contamination occurs pre-harvest, at harvest, and post-harvest at drying, storage, and transportation processes. Interestingly, certain genotypes of peanut have showed moderate resistance to the fungal infection and aflatoxin production. In this study, we had two genotypes in contrast in aflatoxin production that differ in their ability to initiate and/or inhibit aflatoxin production and performed transcriptome profiling at four different time points after inoculation using RNAseq method. This study identified the host-derived candidate transcripts that could control fungal infection and aflatoxin production. These results could help the understanding of peanut responding to the fungal infection and the resulted in aflatoxin contamination. Ultimately, our goal is to develop molecular markers linked to this resistance and apply the markers in genetic breeding selection for resistance to the fungal infection with reduced aflatoxin production.

Technical Abstract: Aflatoxin-affected peanut presents a major global health issue to both commercial and subsistence farming. Therefore, understanding the genetic and molecular mechanisms associated with resistance to aflatoxin production during host-pathogen interactions is crucial for breeding groundnut cultivars with minimal level of aflatoxin contamination. Here, we performed gene expression profiling to better understand the mechanisms involved in reduction and prevention of aflatoxin contamination resulting from Aspergillus flavus infection of groundnut seeds. RNA sequencing (RNAseq) of 16 samples from different time points during infection (24hr, 48hr, 72hr and 7th day after inoculation) in U 4-7-5 (resistant) and JL 24 (susceptible) genotypes yielded 840.5 million raw reads with an average of 52.5 million reads per sample. A total of 1779 unique differentially expressed genes (DEGs) were identified. Furthermore, comprehensive analysis revealed several pathways, such as disease resistance, hormone biosynthetic signaling, flavonoid biosynthesis, ROS detoxifying, cell wall metabolism and catabolizing and seed germination. We also detected several highly upregulated transcription factors, such as ARF, DBB, MYB, NAC and C2H2 in the resistant genotype in comparison to the susceptible genotype after inoculation. Moreover, RNAseq analysis suggested the occurrence of coordinated control of key pathways controlling cellular physiology and metabolism upon A. flavus infection, resulting in reduced aflatoxin production.