title: Identifying differentially expressed genes in pollen from self-incompatible "Wuzishatangju" and self-compatible "Shatangju" mandarins.
abstract: Self-incompatibility (SI) is one of the important factors that can result in seedless fruit in Citrus. However, the molecular mechanism of SI in Citrus is not yet clear. In this study, two suppression subtractive hybridization (SSH) libraries (forward, F and reverse, R) were constructed to isolate differentially expressed genes in pollen from "Wuzishatangju" (SI) and "Shatangju" (self-compatibility, SC) mandarins. Four hundred and sixty-eight differentially expressed cDNA clones from 2077 positive clones were sequenced and identified. Differentially expressed ESTs are possibly involved in the SI reaction of "Wuzishatangju" by regulating pollen development, kinase activity, ubiquitin pathway, pollen-pistil interaction, and calcium ion binding. Twenty five SI candidate genes were obtained, six of which displayed specific expression patterns in various organs and stages after self- and cross-pollination. The expression level of the F-box gene (H304) and S1 (F78) in the pollen of "Wuzishatangju" was 5-fold higher than that in "Shatangju" pollen. The F-box gene, S1, UBE2, UBE3, RNaseHII, and PCP were obviously up-regulated in pistils at 3 d after self-pollination of "Wuzishatangju", approximately 3-, 2-, 10-, 5-, 5-, and 2-fold higher, respectively than that at the same stage after cross-pollination of "Wuzishatangju" × "Shatangju" pistils. The potential involvement of these genes in the pollen SI reaction of "Wuzishatangju" is discussed.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Horticulture, South China Agricultural University, Guangzhou 510642, China. qinyh@scau.edu.cn.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Miao
authors.forename: Zixing
authors.initials: Z
authors.lastname: Ye
authors.forename: Jaime A Teixeira
authors.initials: JA
authors.lastname: da Silva
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Qin
authors.forename: Guibing
authors.initials: G
authors.lastname: Hu
mesh_terms: D002957:Citrus / Q000235:genetics* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D063990:Gene Ontology; D017343:Genes, Plant; D011058:Pollen / Q000235:genetics*; D054817:Pollination / Q000235:genetics; D057945:Self-Fertilization / Q000235:genetics; D060436:Self-Incompatibility in Flowering Plants / Q000235:genetics*