Association of differentially expressed R-gene candidates with leaf spot resistance in peanut (Arachis hypogaea L.)

Abstract

Early leaf spot (ELS) and late leaf spot (LLS) are major fungal diseases of peanut that can severely reduce yield and quality. Development of acceptable genetic resistance has been difficult due to a strong environmental component and many major and minor QTLs. Resistance genes (R-genes) are an important component of plant immune system and have been identified in peanut. Association of specific R-genes to leaf spot resistance will provide molecular targets for marker-assisted breeding strategies. In this study, advanced breeding lines from different pedigrees were evaluated for leaf spot resistance and 76 candidate R-genes expression study was applied to susceptible and resistant lines. Thirty-six R-genes were differentially expressed and significantly correlated with resistant lines, of which a majority are receptor like kinases (RLKs) and receptor like proteins (RLPs) that sense the presence of pathogen at the cell surface and initiate protection response. The largest group was receptor-like cytoplasmic kinases (RLCKs) VII that are involved in pattern-triggered kinase signaling resulting in the production reactive oxygen species (ROS). Four R-genes were homologous to TMV resistant protein N which has shown to confer resistance against tobacco mosaic virus (TMV). When mapped to peanut genomes, 36 R-genes were represented in most chromosomes except for A09 and B09. Low levels of gene-expression in resistant lines suggest expression is tightly controlled to balance the cost of R-gene expression to plant productively. Identification and association of R-genes involved in leaf spot resistance will facilitate genetic selection of leaf spot resistant lines with good agronomic traits.

Sensitivity of Aspergillus flavus Isolates from Peanut Seeds in Georgia to Azoxystrobin, a Quinone outside Inhibitor (QoI) Fungicide

“…Peanuts (Arachis hypogaea L.) are an important source of protein and oil, and are considered to be one of the top oilseeds produced globally [1]. Global peanut production from 2010-2013 averaged over 39 metric tons per year, an increase of 136% since the 1970s [2].…”

“…Global peanut production from 2010-2013 averaged over 39 metric tons per year, an increase of 136% since the 1970s [2]. The U.S. is the 4th largest producer of peanuts worldwide, following China, India, and Nigeria, producing about 5.5 million metric tons per year [1,3]. Within the U.S., the Southeast is the highest producing region, largely due to the humid subtropical-like climate with short and mild winters allowing for longer crop seasons and ideal growing conditions.…”

“…Within the U.S., the Southeast is the highest producing region, largely due to the humid subtropical-like climate with short and mild winters allowing for longer crop seasons and ideal growing conditions. While this climate is ideal for higher production and yield, it also lends itself to many limiting production factors, both biotic and abiotic [1].…”

Single-step genome-wide association study for susceptibility toTeratosphaeria nubilosaand precocity of vegetative phase change inEucalyptus globulus

“…LRR receptor-like serine/threonine-protein kinase GSO1 was reported to be related to the resistance of Nicotiana tabacum to the oomycete Phytophthora parasitica 70 . TMV resistance protein N-like was reported to be involved in the resistance in potato to the fungus Synchytrium endobioticum 71 , and in peanut to two serious fungal foliar diseases 72 . F-Box/LRR repeat protein was reported to be activated by fungal pathogens ( Cladosporium fulvum, Puccinia striiformis ) in different plant species in order to regulate defense responses 73 .…”

Advances in omics research on peanut response to biotic stresses

“…In a comparative transcriptome analysis from resistant line (GPBD 4), resistant introgression line (ICGV 13208) and a susceptible line (TAG 24), the resistance genes for LLS resistance, Aradu.P20JR and Aradu.Z87JB, were revealed on chromosome A02 and A03, respectively ( Gangurde et al., 2021 ). Dang et al. (2021) reported 36 R-genes were markedly correlated with and differentially expressed in resistant lines.…”