Comparative analysis of NBS-LRR genes and their response to Aspergillus flavus in Arachis

Authors: SONG, HUI - University Of Georgia; WANG, PENGFEI - Biotechnology Research And Development Corporation (BRDC); LI, CHANGSHENG - Biotechnology Research And Development Corporation (BRDC); HAN, SUOYI - Henan Agricultural University; ZHAO, CHUANZHI - Biotechnology Research And Development Corporation (BRDC); XIA, HAN - Biotechnology Research And Development Corporation (BRDC); BI, YUPING - Biotechnology Research And Development Corporation (BRDC); ZHANG, XINYOU - Henan Agricultural University; Guo, Baozhu; WANG, XINGJUN - Biotechnology Research And Development Corporation (BRDC)

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2017
Publication Date: 2/3/2017
Citation: Song, H., Wang, P., Li, C., Han, S., Zhao, C., Xia, H., Bi, Y., Zhang, X., Guo, B., Wang, X. 2017. Comparative analysis of NBS-LRR genes and their response to Aspergillus flavus in Arachis. PLoS One. 12(2):e0171181. doi: 10.1371/journal.pone.0171181.

Interpretive Summary: Peanut, as an important food and oil crop, is grown throughout the tropics and subtropics, but contamination with aflatoxin is a food safety concern to human health. Previous studies showed that disease resistance of wild peanut was higher than that of cultivated peanut. Identification and characterization of genes from wild or cultivated peanut resistance to Aspergillus flavus is important for peanut breeding and genetic improvement of peanut resistance to diseases. The genome sequences of two wild peanuts have been released and published recently (February 2016). The present study conducted systematic analysis of genes from wild peanut Arachis duranensis and A. ipaënsis. The chromosomal location of these genes, gene cluster and phylogenetic relationships were analyzed. The expression of NBS-LRR genes, which have been associated with disease resistance in other species, were characterized in A. duranensis and cultivated peanut (Luhua 14) under A. flavus treatment. These genes were highly expressed in A. duranensis but not in A. hypogaea under treatment with A. flavus. The results indicated that these genes from A. duranensis showed induced responses to A. flavus treatment at transcription level, and further research will improve the understanding of the regulation of disease resistance genes in wild and cultivated peanuts, and provide information for the utilization of wild peanut germplasm resource for cultivated peanut improvement.

Technical Abstract: NBS-LRR genes have been demonstrated as response to pathogen attack in different plant species. Characterization of NBS-LRR genes in peanut is not well documented. The newly released whole genome sequences of Arachis duranensis and Arachis ipaënsis have provided the opportunity to conduct the global analysis of this important gene family in peanut. In this study, we identified 393 (AdNBS) and 437 (AiNBS) NBS-LRR genes from A. duranensis and A. ipaënsis, respectively, by bioinformatics approach. Among these genes, full-length sequences of 278 AdNBS and 303 AiNBS were identified. Sixty-four orthologous gene pairs and seven paralogous AdNBS and 13 paralogous AiNBS gene pairs were predicted. Most paralogous gene pairs were located in the same chromosomes, indicating tandem duplication was the driving force in forming these paralogous. These paralogous genes mainly underwent purify selection, but most LRR8 domains underwent positive selection. Most NBS-LRR genes were distributed on chromosomes A2 and B2 while the least genes were located on chromosomes A6 and B7. More gene clusters were found in A. ipaënsis than that in A. duranensis, possibly due to the tandem duplication events occurred more frequently in A. ipaënsis. The expressions of three genes in A. duranensis and A. hypogaea were analyzed by qRT-PCR. These genes were highly expressed in A. duranensis but not in A. hypogaea under treatment with Aspergillus flavus. The results indicated that these genes from A. duranensis showed induced responses to A. flavus treatment at transcription level, and further research will improve the understanding of the regulation of disease resistance genes after polyploidization and domestication, and provide information for the utilization of wild germplasm resource.