title: Genome-Wide Analysis of Sorbitol Dehydrogenase (SDH) Genes and Their Differential Expression in Two Sand Pear (Pyrus pyrifolia) Fruits.
abstract: Through RNA-seq of a mixed fruit sample, fourteen expressed sorbitol dehydrogenase (SDH) genes have been identified from sand pear (Pyrus pyrifolia Nakai). Comparative phylogenetic analysis of these PpySDHs with those from other plants supported the closest relationship of sand pear with Chinese white pear (P. bretschneideri). The expression levels varied greatly among members, and the strongest six (PpySDH2, PpySDH4, PpySDH8, PpySDH12, PpySDH13 and PpySDH14) accounted for 96% of total transcript abundance of PpySDHs. Tissue-specific expression of these six members was observed in nine tissues or organs of sand pear, with the greatest abundance found in functional leaf petioles, followed by the flesh of young fruit. Expression patterns of these six PpySDH genes during fruit development were analyzed in two sand pear cultivars, "Cuiguan" and "Cuiyu". Overall, expression of PpySDHs peaked twice, first at the fruitlet stage and again at or near harvest. The transcript abundance of PpySDHs was higher in "Cuiguan" than in "Cuiyu", accompanied by a higher content of sugars and higher ratio of fructose to sorbitol maintained in the former cultivar at harvest. In conclusion, it was suggested that multiple members of the SDH gene family are possibly involved in sand pear fruit development and sugar accumulation and may affect both the sugar amount and sugar composition.
authors.affiliation: Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, China. daimeisong@163.com.|Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. daimeisong@163.com.
authors.forename: Meisong
authors.initials: M
authors.lastname: Dai
authors.affiliation: Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. shizebinszb@126.com.
authors.forename: Zebin
authors.initials: Z
authors.lastname: Shi
authors.affiliation: Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, China. chjxu@zju.edu.cn.
authors.forename: Changjie
authors.initials: C
authors.lastname: Xu
mesh_terms: D005638:Fruit / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D018745:Genome, Plant; D055106:Genome-Wide Association Study; D007064:L-Iditol 2-Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D031989:Pyrus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D007064:L-Iditol 2-Dehydrogenase
keywords: RNA-seq; fruit development; ratio of fructose to sorbitol; sand pear; sorbitol dehydrogenase (SDH) gene family; sugar accumulation