Genetic and physiological analyses of root cracking in radish (Raphanus sativus L.)

• Published in: Theoretical and applied genetics Vol. 132; no. 12; pp. 3425 - 3437
• Main Authors: Yu, Xiaona, Choi, Su Ryun, Chhapekar, Sushil Satish, Lu, Lu, Ma, Yinbo, Lee, Ji-Young, Hong, Seongmin, Kim, Yoon-Young, Oh, Sang Heon, Lim, Yong Pyo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2019; Springer; Springer Nature B.V
• Subjects: Adaptation; Agriculture; Biochemistry; Biomedical and Life Sciences; Biotechnology; Calcium Channels - genetics; Calcium Signaling; Calcium signalling; Calcium transport; Cell walls; Cellular signal transduction; Chromosome Mapping; Cultivars; Developmental stages; Genes; Genes, Plant; Genetic analysis; Genetic aspects; Genetic Linkage; Life Sciences; Original Article; Phenotypes; Physiological aspects; Physiology; Plant Biochemistry; Plant breeding; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Roots - genetics; Plant Roots - growth & development; Polymorphism, Single Nucleotide; Protein binding; Proteins; Quantitative genetics; Quantitative Trait Loci; Raphanus - genetics; Raphanus sativus; Signal transduction; Transduction; South Korea; Quantitative trait loci (QTLs); Radish; Calcium; Root cracking; Calmodulin-dependent protein kinase (CDPK); Cell wall
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-019-03435-9

Key message
A major QTL conferring tolerance to radish (
Raphanus sativus
) root cracking was mapped for the first time and two calcium regulatory genes were identified that positively associated with the cracking phenomenon.
Root cracking is a severe physiological disorder that significantly decreases the yield and commercial value of radish. The genetic and physiological mechanisms underlying this root cracking disorder have not been characterized. In this study, quantitative trait loci (QTLs) putatively associated with radish root cracking were mapped. Ten QTLs were distributed in six linkage groups, among these QTLs, ‘
RCr1
’ in LG1 was detected over 3 consecutive years and was considered to be a major QTL for root cracking. The QTL ‘
RCr1
’ was responsible for 4.47–18.11% of variance in the root cracking phenotype. We subsequently identified two candidate genes,
RsANNAT
and
RsCDPK
. Both genes encode proteins involved in calcium binding, ion transport, and Ca
2+
signal transduction, which are important for regulating plant development and adaptations to the environment. These genes were co-localized to the major QTL region. Additionally, we analyzed physiological changes (i.e., root firmness, cell wall content, and cell-wall-bound calcium content) in two parental lines during different developmental stages. Moreover, we observed that the
RsANNAT
and
RsCDPK
expression levels are positively correlated with Ca
2+
contents in the roots of the cracking-tolerant ‘835’ cultivar. Thus, these genes may influence root cracking. The data provided herein may support the useful information to understand root cracking behavior in radish and may enable breeders to develop new cultivars exhibiting increased tolerance to root and fruit cracking.