Journals
  Publication Years
  Keywords
Search within results Open Search
Please wait a minute...
For Selected: Toggle Thumbnails
The PcHY5 methylation is associated with anthocyanin biosynthesis and transport in ‘Max Red Bartlett’ and ‘Bartlett’ pears
WEI Wei-lin, JIANG Fu-dong, LIU Hai-nan, SUN Man-yi, LI Qing-yu, CHANG Wen-jing, LI Yuan-jun, LI Jia-ming, WU Jun
2023, 22 (11): 3256-3268.   DOI: 10.1016/j.jia.2023.07.017
Abstract204)      PDF in ScienceDirect      

The red coloring of pear fruits is mainly caused by anthocyanin accumulation.  Red sport, represented by the green pear cultivar ‘Bartlett’ (BL) and the red-skinned derivative ‘Max Red Bartlett’ (MRB), is an ideal material for studying the molecular mechanism of anthocyanin accumulation in pear.  Genetic analysis has previously revealed a quantitative trait locus (QTL) associated with red skin color in MRB.  However, the key gene in the QTL and the associated regulatory mechanism remain unknown.  In the present study, transcriptomic and methylomic analyses were performed using pear skin for comparisons between BL and MRB.  These analyses revealed differential PcHY5 DNA methylation levels between the two cultivars; MRB had lower PcHY5 methylation than BL during fruit development, and PcHY5 was more highly expressed in MRB than in BL.  These results indicated that PcHY5 is involved in the variations in skin color between BL and MRB.  We further used dual luciferase assays to verify that PcHY5 activates the promoters of the anthocyanin biosynthesis and transport genes PcUFGT, PcGST, PcMYB10 and PcMYB114, confirming that PcHY5 not only regulates anthocyanin biosynthesis but also anthocyanin transport.  Furthermore, we analyzed a key differentially methylated site between MRB and BL, and found that it was located in an intronic region of PcHY5.  The lower methylation levels in this PcHY5 intron in MRB were associated with red fruit color during development, whereas the higher methylation levels at the same site in BL were associated with green fruit color.  Based on the differential expression and methylation patterns in PcHY5 and gene functional verification, we hypothesize that PcHY5, which is regulated by methylation levels, affects anthocyanin biosynthesis and transport to cause the variations in skin color between BL and MRB.

Reference | Related Articles | Metrics
Comparative transcriptome analysis provides insights into the mechanism of pear dwarfing
TANG Zi-kai, SUN Man-yi, LI Jia-ming, SONG Bo-bo, LIU Yue-yuan, TIAN Yi-ke, WANG Cai-hong, WU Jun
2022, 21 (7): 1952-1967.   DOI: 10.1016/S2095-3119(21)63774-7
Abstract279)      PDF in ScienceDirect      
Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.  However, dwarfing cannot be widely applied in the cultivation of pears, especially Asian pears.  Developing varieties with dwarf characteristics is a goal of paramount importance in pear breeding.  In the present study, dwarf phenotype pears (DPPs) and arborescent phenotype pears (APPs) were obtained from the offspring of a cross between ‘Aiyuxiang’ and ‘Cuiguan’ pear cultivars, which exhibited dwarfed and arborescent statures, respectively.  When compared with APPs, the heights of DPPs showed a 62.8% reduction, and the internode lengths were significantly shorter.  Cross-grafting between DPPs and APPs demonstrated that the dwarfed phenotype of DPPs was primarily induced by the aerial portions of the plant, and independent of the root system.  Observations of stem tissue sections showed that DPP cells were arranged chaotically with irregular shapes, and the average length was larger than that of the APP cells.  A total of 1 401 differently expressed genes (DEGs) in shoot apices between DPPs and APPs were identified by RNA-sequencing (RNA-Seq), and these DEGs were mainly enriched in the ‘phytohormone-related pathways, cell wall metabolism and cell division’ categories.  Moreover, 101 DEGs were identified as transcription factors (TFs).  In DPPs, several brassinosteroids (BR) signaling and cell cycle-related genes were significantly down-regulated, while genes involved in BR and GA degradation were up-regulated.  Comprehensive analysis of RNA-Seq data and stem tissue sections suggested that the dwarfed phenotype of DPPs could be primarily attributed to deficiencies in cell division.  Previous work using simple sequence repeat (SSR) markers narrowed the location of the gene responsible for the dwarf phenotype of ‘Le Nain Vert’.  Through combined analysis of our transcriptomic data with the SSR results, we identified four genes as promising candidates for the dwarf phenotype, among which, a DELLA gene could be the most promising.  The results presented in this study provide a sound foundation for further exploration into the genetic and molecular mechanisms underlying pear dwarfing.
Reference | Related Articles | Metrics