Main content area

Ploidy manipulation via cell engineering for citrus improvement facilitated by application of molecular markers

Guo, Wen-Wu, Xie, Kai-Dong, Wu, Xiao-Meng, Xie, Zong-Zhou, Xu, Qiang, Deng, Xiu-Xin
Acta horticulturae 2018 no.1203 pp. 105-110
Citrus, allotetraploidy, anther culture, callus, cell engineering, cultivars, cybrids, cytoplasm, cytoplasmic male sterility, diploidy, flow cytometry, genetic markers, haploidy, mesophyll, microsatellite repeats, ovule culture, parents, pollen, pollination, protoplasts, seedless varieties, somatic hybridization, triploidy
Polyploid cultivars produced via cell engineering are a valuable germplasm resource for citrus improvement. Application of molecular markers can greatly enhance the efficiency of citrus breeding via cell engineering. In our program, allotetraploid somatic hybrids were produced from over 50 interspecific or intergeneric fusion combinations, and characterized by molecular markers. We also exploited plenty of double diploids facilitated by flow cytometry and simple sequence repeat (SSR) marker analysis. Some of the somatic hybrids and double diploids have served as pollen parents for interploidy sexual crossing, and thousands of triploid plants were recovered by embryo rescue, flow cytometry and SSR marker analysis. Based on molecular marker analysis of numerous citrus somatic hybrids and cybrids, a strategy of producing male-sterile cybrids was developed. It consists of a standard symmetric fusion of the protoplasts from embryogenic callus induced from 'Satsuma' mandarin (cytoplasmic male-sterility type) with mesophyll protoplasts of elite seedy cultivars. Some of the regenerated diploid cybrids containing sterile cytoplasm from 'Satsuma' have already displayed male sterility and seedlessness. Understanding the molecular mechanism of male sterility in a citrus somatic cybrid was conducted via omics approaches. Haploids and di-haploids were also regenerated via anther culture or pollination with gamma-irradiated pollen, and molecularly characterized.