Understanding the Sorghum–Colletotrichum sublineola Interactions for Enhanced Host Resistance

Abstract

Improving sorghum resistance is a sustainable method to reduce yield losses due to anthracnose, a devastating disease caused by Colletotrichum sublineola. Elucidating the molecular mechanisms of sorghum–C. sublineola interactions would help identify biomarkers for rapid and efficient identification of novel sources for host-plant resistance improvement, understanding the pathogen virulence, and facilitating resistance breeding. Despite concerted efforts to identify resistance sources, the knowledge about sorghum–anthracnose interactions remains scanty. Hence, in this review, we presented an overview of the current knowledge on the mechanisms of sorghum-C. sublineola molecular interactions, sources of resistance for sorghum breeding, quantitative trait loci (QTL), and major (R-) resistance gene sequences as well as defense-related genes associated with anthracnose resistance. We summarized current knowledge about C. sublineola populations and its virulence. Illustration of the sorghum-C. sublineola interaction model based on the current understanding is also provided. We highlighted the importance of genomic resources of both organisms for integrated omics research to unravel the key molecular components underpinning compatible and incompatible sorghum–anthracnose interactions. Furthermore, sorghum-breeding strategy employing rapid sorghum germplasm screening, systems biology, and molecular tools is presented.

Evaluation of a Subset of Ethiopia Sorghum Collection Germplasm from the National Genetic Resources Program of the United States Department of Agriculture for Anthracnose Resistance

“…The most effective option for managing sorghum anthracnose in production fields is the use of resistant sources [2] [12] [13] [14] [15] [24] [25]. However, the presence of different pathotypes of the pathogen [8] [20] [21] [22] requires the need to continually evaluate diverse germplasm to identify stable resistant sources.…”

“…ture food stability, especially in resource-poor drier agro-ecological regions [1] [2] [3]. This versatile drought-tolerant crop will continue to gain in importance for its varied uses as the environment becomes less predictable due to climate change and those looking for healthy diet options [2] [4] [5] [6]. Nevertheless, increases in sorghum production will likely increase biotic stresses due to microorganisms, such as the fungus Colletotrichum sublineola (Henn.…”

“…The most effective and environmentally sound management strategy for sorghum anthracnose is the use of resistant genotypes [2] [11] [12] [13] [14] [15]. Many resistant sources from different sorghum-growing regions have been reported [1] [11] [12] [13] [15] [16] [17] [18] [19].…”

Identification and Characterization of Colletotrichum Species Causing Sorghum Anthracnose in Kenya and Screening of Sorghum Germplasm for Resistance to Anthracnose

“…It is known that anthracnose has a strong negative impact on grain-filling and this result in a large amount of yield losses on susceptible genotypes. In addition, the conidia of C. sublineolum , when they are inside the plant, interfere with water and nutrient movement in the vascular tissues resulting in poor development of the panicle and grain [ 55 ]. Foliar anthracnose causes damages to the leaves and stalk rot reducing the photosynthetic area which results in a reduction in grain sizes, grain weight and subsequent yield losses [ 56 ].…”

Variation in Gene Expression between Two Sorghum bicolor Lines Differing in Innate Immunity Response

“…In sorghum, these strategies include activation of PR proteins [ 26 ], accumulation of hydrogen peroxide [ 27 ], and biosynthesis of flavonoid phytoalexins [ 28 ]. Different approaches have been used to study sorghum’s resistance responses, identify defense compounds, and identify physical barriers against anthracnose (see reference [ 29 , 30 ] for review). Gene expression studies were widely used to identify candidate resistance genes in plants based on the differential expression between resistant and susceptible cultivars or non-inoculated and pathogen inoculated plants (e.g., references [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]).…”