Disassembly of the fruit cell wall by the ripening-associated polygalacturonase and expansin influences tomato cracking  

作　　者：Fangling Jiang Alfonso Lopez Shinjae Jeon Sergio Tonetto de Freitas Qinghui Yu Zhen Wu John M.Labavitch Shengke Tian Ann L.T.Powell Elizabeth Mitcham 

机构地区：[1]Department of Horticulture,Nanjing Agricultural University,Nanjing 210095,China [2]Department of Plant Sciences,University of California,Davis 95616,USA [3]Gangwon Agricultural Research and Extension Services,Chuncheon 200-150,South Korea [4]Institute of Vegetables,Xinjiang Academy of AgriculturalSciences,830091 Urumchi,China [5]College of Environmental and Resource Sciences,Zhejiang University,310058 Hangzhou,China

出　　处：《Horticulture Research》2019年第1期1545-1559,共15页园艺研究（英文）

基　　金：supported by National Natural Science Foundation of China(31701924);the National Science Foundation(US IOS 0957264);Fundamental Research Funds for the Central Universities,China(KYZ201609);the US NSF support to ALTP(IOS 0544504 and 0957264).

摘　　要：Fruit cracking is an important problem in horticultural crop production.Polygalacturonase(SlPG)and expansin(SlEXP1)proteins cooperatively disassemble the polysaccharide network of tomato fruit cell walls during ripening and thereby,enable softening.A Golden 2-like(GLK2)transcription factor,SlGLK2 regulates unripe fruit chloroplast development and results in elevated soluble solids and carotenoids in ripe fruit.To determine whether SlPG,SlEXP1,or SlGLK2 influence the rate of tomato fruit cracking,the incidence of fruit epidermal cracking was compared between wild-type,Ailsa Craig(WT)and fruit with suppressed SlPG and SlEXP1 expression(pg/exp)or expressing a truncated nonfunctional Slglk2(glk2).Treating plants with exogenous ABA increases xylemic flow into fruit.Our results showed that ABA treatment of tomato plants greatly increased cracking of fruit from WT and glk2 mutant,but not from pg/exp genotypes.The pg/exp fruit were firmer,had higher total soluble solids,denser cell walls and thicker cuticles than fruit of the other genotypes.Fruit from the ABA treated pg/exp fruit had cell walls with less water-soluble and more ionically and covalently-bound pectins than fruit from the other lines,demonstrating that ripening-related disassembly of the fruit cell wall,but not elimination of SlGLK2,influences cracking.Cracking incidence was significantly correlated with cell wall and wax thickness,and the content of cell wall protopectin and cellulose,but not with Ca^(2+)content.

关 键 词：fir walls CRACKING 

分 类 号：S64[农业科学—蔬菜学]