Expression Quantitative Trait Loci (eQTL) mapping for callose synthases in intergeneric hybrids of Citrus challenged with the bacteria Candidatus Liberibacter asiaticus

Abstract

Citrus plants have been extremely affected by Huanglongbing (HLB) worldwide, causing economic losses. HLB disease causes disorders in citrus plants, leading to callose deposition in the phloem vessel sieve plates. Callose is synthesized by callose synthases, which are encoded by 12 genes (calS1-calS12) in Arabidopsis thaliana. We evaluated the expression of eight callose synthase genes from Citrus in hybrids between Citrus sunki and Poncirus trifoliata infected with HLB. The objective of this work was to identify possible tolerance loci combining the expression quantitative trait loci (eQTL) of different callose synthases and genetic Single-Nucleotide Polymorphism (SNP) maps of C. sunki and P. trifoliata. The expression data from all CscalS ranged widely among the hybrids. Furthermore, the data allowed the detection of 18 eQTL in the C. sunki map and 34 eQTL in the P. trifoliata map. In both maps, some eQTL for different CscalS were overlapped; thus, a single region could be associated with the regulation of more than one CscalS. The regions identified in this work can be interesting targets for future studies of Citrus breeding programs to manipulate callose synthesis during HLB infection.

Resistance inducers and organic fertilizer in Citrus sinensis [L.] Osbeck infected with Candidatus Liberibacter asiaticus bacteria

“…Also, along with within the characteristic symptomatology of Huanglongbing, develops an irregular asymmetry and smaller size in fruits, pericarp thickening, seeds abortion, color inversion and reduction of soluble solids, this last characteristic deteriorates the organoleptic quality, which, therefore, is not possible to use it in the juice industry (Sáenz et al, 2019). Currently, there is no known cure for this disease (Curtolo et al, 2020). However, there are various capable resistance inducing chemical agents in plants (Acuña and Grabowski, 2012).…”

fullsibQTL: an R package for QTL mapping in biparental populations of outcrossing species

“…It implements the model proposed by Gazaffi et al (2014), allowing to estimate the number of QTLs, their position, effects, segregation patterns, and linkage phases with flanking markers. This methodology has been successfully applied in different studies (Souza et al, 2013;Margarido et al, 2015;Costa et al, 2016;Balsalobre et al, 2017;da Silva Pereira et al, 2017;Barreto et al, 2018;Conson et al, 2018;Curtolo et al, 2020;Soratto et al, 2020), but currently there is no competing software with such features.…”