Introgression of heat shock protein (Hsp70 and sHsp) genes into the Malaysian elite chilli variety Kulai (Capsicum annuum L.) through the application of marker-assisted backcrossing (MAB)

Abstract

Backcrossing together with simple sequence repeat marker strategy was adopted to improve popular Malaysian chilli Kulai (Capsicum annuum L.) for heat tolerance. The use of molecular markers in backcross breeding and selection contributes significantly to overcoming the main drawbacks such as increase linkage drag and time consumption, in the ancient manual breeding approach (conventional), and speeds up the genome recovery of the recurrent parent. The strategy was adopted to introgress heat shock protein gene(s) from AVPP0702 (C. annuum L.), which are heat-tolerant, into the genetic profile of Kulai, a popular high-yielding chilli but which is heat sensitive. The parents were grown on seed trays, and parental screening was carried out with 252 simple sequence repeat markers. The selected parents were crossed and backcrossed to generate F hybrids and backcross generations. Sixty-eight markers appeared to be polymorphic and were used to assess the backcross generation; BCF, BCF and BCF. The average recipient allele of the selected four BCF plants was 80.75% which were used to produce the BCF generation. BC-P was the best BCF plant because it had the highest recovery at 83.40% and was positive to Hsp-linked markers (Hsp70-u2 and AGi42). After three successive generations of backcrossing, the average genome recovery of the recurrent parent in the selected plants in BCF was 95.37%. Hsp gene expression analysis was carried out on BCF, BCF and BCF selected lines. The Hsp genes were found to be up-regulated when exposed to heat treatment. The pattern of Hsp expression in the backcross generations was similar to that of the donor parent. This confirms the successful introgression of a stress-responsive gene (Hsp) into a Kulai chilli pepper variety. Furthermore, the yield performance viz. plant height, number of fruits, fruit length and weight and total yield of the improved plant were similar with the recurrent parent except that the plant height was significantly lower than the Kulai (recurrent) parent.

Drought Resistance in Rice from Conventional to Molecular Breeding: A Review

“…The general terms used in modern breeding methods include marker-assisted selection (MAS), marker-assisted pedigree selection (MAPS), genomic selection (GS) or genome-wide selection (GWS), marker-assisted recurrent selection (MARS) and marker-assisted backcrossing (MABC). From the methods listed above, MABC is the most effective and widely used method [101,102,103]. When a gene is responsible for a high percentage of phenotypic traits or the expression of a desirable trait is controlled by a single gene, then the transfer of a specific region from a donor parent to the recipient parent can show a significant improvement in such trait using MABC.…”

Heat Shock Proteins: Dynamic Biomolecules to Counter Plant Biotic and Abiotic Stresses

“…Cytosolic HSP70 was involved in heat stress tolerance in Arabidopsis [148]. HSP70s have been studied under high temperature stress in a variety of plant crops; such as witch-grass and alfalfa [149,150]; vegetables like pepper, tomato, cabbage, potato; ornamental plants like chrysanthemum [151,152,153,154,155,156,157]; grain such as wheat [158]; and tea [159]. Xu et al, (2010) [160] observed the expression pattern of chloroplast HSP60, not only in normal conditions but, also, under high-temperature and drought situations.…”

AtHsc70‐1 negatively regulates the basal heat tolerance in Arabidopsis thaliana through affecting the activity of HsfAs and Hsp101

“…Hsp70s form a central hub of molecular chaperone networks that control protein homeostasis in prokaryotes and eukaryotes. These proteins facilitate the folding of newly‐synthesized proteins, prevent proteins from aggregating, control transport of cellular proteins across membranes, modulate protein activity, and bring about regulation of protein degradation in adverse environmental conditions (Sung et al ., 2001; Wegele et al ., 2004; Mayer and Bukau, 2005; Rajan and D’Silva, 2009; Saibil, 2013; Verma et al ., 2017; Usman et al ., 2018). Arabidopsis genome contains 18 Hsp70 members (Lin et al ., 2001), Saccharomyces cerevisiae 14 members (Walsh et al ., 2004), Escherichia coli three members, and rice 32 members (Sarkar et al ., 2013).…”