Evaluating Walnut (Juglans spp.) for resistance to walnut blight and comparisons between artificial inoculation assays and field studies

Transcriptome Responses of Wild Arachis to UV-C Exposure Reveal Genes Involved in General Plant Defense and Priming

“…A. stenosperma detached leaves were used here as explants based on the extensive literature that successfully describes its use for molecular characterization of responses to UV stress in leaves of many plant species, including wild Arachis [ 21 , 22 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. In addition, detached-leaves assays are an accurate methodology to produce large sample sizes, strengthening the accuracy of the statistics [ 40 , 41 , 42 , 43 ]. However, it is important to point out that, using this approach, some of the DEGs identified as responsive to UV might also be simultaneously responsive to wounding stress that intrinsically occurred when leaves were detached from plants.…”

“…The controlled environment of detached-leaf assays can overcome limitations imposed by field and greenhouse evaluations conducted with whole plants, allowing more standardized assessments and improving the number and homogeneity of samples that could be evaluated. Detached-leaf assays are particularly a practical and suitable experimental procedure for a heterogeneous group of plants, which is intrinsically the case for several wild, perennial, and/or large-size species, showing significant data correlations with whole-plant assays [ 40 , 41 , 42 , 43 ].…”

Resistance evaluation of walnut (Juglans spp.) against Xanthomonas arboricola and the correlation between leaf structure and resistance

“…Juglans regia was reported to be the most sensitive species, while J. sigillata, the native species in China, was more resistant than J. regia in the field (Belisario et al, 2010;McNeil, 2014). Due to the time of leaf-expansion period and the rainy season largely coinciding, and rainfall and heat resources in the same seasons, the environment at this time is conducive to bacterial infection in the walnut producing regions of south-western China (Jiang et al, 2019). Although agronomic, genetic and biological approaches have been proposed to limit yield losses caused by biotic stress, disease management is still based on chemical control, which is not sustainable (Funk et al, 1981;Neely, 1981).…”

“…The four HR genotypes with much fewer lesions formed included two J. sigillata('86' and '91') genotypes, one J. regia ('Qingxiang') and one J. regia × J. sigillata ('Chuanzao2').Highly resistant walnut cultivars are valuable resources for disease resistance breeding programmes(Jiang et al, 2019;Soltani & Aliabadi, 2010) Jiang et al (2019),. obtained similar results to those reported here when evaluating walnut for resistance to walnut blight through artificial inoculation assays and field studies(Jiang et al, 2019). Consequently, walnuts of high resistance to Xaj like '86','91', 'Chuanzao2' and 'Qingxiang' may decrease pesticide requirements in walnut orchards, protect cultivation systems and enhance the variety and yield of nuts.…”

Hybrid Breeding for Restoration of Threatened Forest Trees: Evidence for Incorporating Disease Tolerance in Juglans cinerea

“…Conversely, in another study, hybrids of Persian walnut (Juglans regia L.) and iron walnut (Juglans sigllata Dode) showed similar or even greater susceptibility to walnut bacterial blight (Xanthomonas arboricola pv. juglandis Pierce) than both their progenitors (Jiang et al, 2019). Heightened susceptibility to crown gall disease (Agrobacterium tumefaciens Smith & Townsend) has also been documented in hybrids of northern California black walnut [Juglans hindsii (Jeps.)…”