ERWINIA-CAROTOVORA SUBSP CAROTOVORA PECTIC ENZYMES - INPLANTA GENE ACTIVATION AND ROLES IN SOFT-ROT PATHOGENESIS

被引：26

作者：

YANG, Z ^{[1
]}

CRAMER, CL ^{[1
]}

LACY, GH ^{[1
]}

机构：

[1] VIRGINIA POLYTECH INST & STATE UNIV,DEPT PLANT PATHOL PHYSIOL & WEED SCI,BLACKSBURG,VA 24061

来源：

MOLECULAR PLANT-MICROBE INTERACTIONS | 1992年 / 5卷 / 01期

关键词：

D O I：

10.1094/MPMI-5-104

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Pectic enzyme expression in Erwinia carotovora subsp. carotovora was studied on potato tuber slices using a membrane-separated system. Accumulation of mRNAs was sequential for exo-pectate lyase (exo-PL), endo-PL, and endo-polygalacturonase, respectively, and reached maxima by 6-12 hr. Induction kinetics in vitro with polygalacturonic acid differed from inplanta kinetics. Accumulations of mRNA were correlated with rotting; under conditions incompatible with pathogenesis, induction was reduced, and exo-PL expression was delayed. Healed slices were resistant to rotting, but challenging E. c. subsp. carotovora were activated for transient endo-PL expression. This suggests that enzyme induction involves cell wall degradation products. Pretreatment of slices with Escherichia coli expressing E. c. subsp. carotovora exo-PL increased in planta accumulation of mRNAs for all three pectic enzymes in E. c. subsp. Carotovora applied as a subsequent challenge, indicating that exo-PL reaction products activate other pectic enzyme genes. Endo-PL, expressed from E. coli, induced host accumulation of mRNAs for phenylalanine ammonia-lyase, a marker for plant defense-responses. These results support the hypothesis that pectic enzymes affect virulence by regulating pectic enzyme levels and affect host responses by inducing defense genes.

引用

页码：104 / 112

页数：9