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Overexpression of SpWRKY1 promotes resistance to Phytophthora nicotianae and tolerance to salt and drought stress in transgenic tobacco
Author(s) -
Li Jingbin,
Luan Yushi,
Liu Zhen
Publication year - 2015
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12315
Subject(s) - methyl jasmonate , wrky protein domain , abscisic acid , phytophthora nicotianae , biology , salicylic acid , phenylalanine ammonia lyase , superoxide dismutase , chlorophyll , botany , phytophthora , peroxidase , biochemistry , gene , arabidopsis , antioxidant , mutant , enzyme
WRKY transcription factors are key regulatory components of plant responses to biotic and abiotic stresses. SpWRKY1 , a pathogen‐induced WRKY gene, was isolated from tomato ( Solanum pimpinellifolium L3708 ) using in silico cloning and reverse transcriptase‐polymerase chain reaction ( RT‐PCR ) methods. SpWRKY1 expression was significantly induced following oomycete pathogen infection and treatment with salt, drought, salicylic acid ( SA ), methyl jasmonate ( MeJA ) and abscisic acid ( ABA ). Overexpression of SpWRKY1 in tobacco conferred greater resistance to Phytophthora nicotianae infection, as evidenced by lower malondialdehyde ( MDA ) content; relative electrolyte leakage ( REL ); higher chlorophyll content; and higher peroxidase ( POD , EC 1.11.1.7), superoxide dismutase ( SOD , EC 1.15.1.1) and phenylalanine ammonia‐lyase ( PAL , EC 4.3.1.24) activities. This resistance was also coupled with enhanced expression of SA ‐ and JA ‐associated genes ( NtPR1 , NtPR2 , NtPR4 , NtPR5 and NtPDF1.2 ), as well as of various defense‐related genes ( NtPOD , NtSOD and NtPAL ). In addition, transgenic tobacco plants also displayed an enhanced tolerance to salt and drought stresses, mainly demonstrated by the transgenic lines exhibiting lower accumulation of MDA content and higher POD ( EC 1.11.1.7), SOD ( EC 1.15.1.1) activities, chlorophyll content, photosynthetic rate and stomatal conductance, accompanied by enhanced expression of defense‐related genes ( NtPOD , NtSOD , NtLEA5 , NtP5CS and NtNCED1 ) under salt and drought stresses. Overall, these findings suggest that SpWRKY1 acts as a positive regulator involved in tobacco defense responses to biotic and abiotic stresses.