Resistance to Xanthomonas perforans race T4 causing bacterial spot in tomato breeding lines

Abstract

Tomato (Solanum lycopersicum) is the second most important vegetable crop in the world. Bacterial spot (BS) of tomato, caused by four species of Xanthomonas: X. euvesicatoria, X. vesicatoria, X. perforans and X. gardneri, results in severe loss in yield and quality due to defoliation and formation of lesions on fruits, respectively. Currently management practices do not offer effective control under conditions of high disease pressure. Thus, developing BS resistance is a critical priority for tomato growers in order to minimize crop losses. Sixty‐three advanced tomato breeding lines, heirlooms and wild tomato lines with diverse genetic backgrounds were screened under greenhouse and field conditions for BS resistance using X. perforans race T4, which was found to be a prevalent race in North Carolina. Race T4 isolate 9 was used to inoculate the plants by spraying, and disease severity was measured using the Horsfall–Barratt scale. Tomato lines 74L‐1W(2008), NC2CELBR, 081‐12‐1X‐gsms, NC22L‐1 (2008) and 52LB‐1 showed resistance to BS in the field and/or greenhouse trials. These lines were derived from S. pimpinellifolium L3707. Screening L3707 followed by development of a mapping population and mapping resistance genes might be useful for breeding resistance against BS in future breeding programmes.

Diversity among Modern Tomato Genotypes at Different Levels in Fresh-Market Breeding

“…There have been many types of researches on finding resistance to diseases like bacterial spot; however, no single cultivar has been developed that can resist all races of Xanthomonas causing bacterial spot making this disease a very difficult problem to overcome [34]. This explains the low correlation of bacterial spot with any other traits observed in this study as seen in a previous study [35], whereas resistance to fungal diseases like early blight, late blight, fusarium, and verticillium wilts and nematode resistance have been identified and are already being introgressed in new varieties [36].…”

A centenary for bacterial spot of tomato and pepper

“…Resistance to X. euvesicatoria pv. perforans race T4 in tomato breeding lines was reported by Bhattarai et al (2017). Stall et al (2009) described the progress in the cloning of avirulence genes and identification of resistance-related genes in tomato and pepper over the past several decades.…”

Advances and Challenges in Bacterial Spot Resistance Breeding in Tomato (Solanum lycopersicum L.)

“…Bhattarai, et al [42] reported the moderate level of resistance against race T4 in S. pimpinellifolium derived breeding lines, including 74L-1W (2008), NC2CELBR, 081-12-1X-gsms, NC22L-1 (2008), and 52LB-1, in the field and greenhouse studies. Further work is needed to characterize the resistance observed in these lines and to evaluate if the observed resistance in these lines is sufficient to manage the disease before integrating the resistance in the cultivar.…”