RAP2.6L overexpression delays waterlogging induced premature senescence by increasing stomatal closure more than antioxidant enzyme activity
Waterlogging usually results from overuse or poor management of irrigation water and is a serious constraint due to its damaging effects. RAP2.6L (At5g13330) overexpression enhances plant resistance to jasmonic acid, salicylic acid, abscisic acid (ABA) and ethylene in Arabidopsis thaliana. However, it is not known whether RAP2.6L overexpression in vivo improves plant tolerance to waterlogging stress. In this study, the RAP2.6L transcript was induced by waterlogging or an ABA treatment, which was reduced after pretreatment with an ABA biosynthesis inhibitor tungstate. Water loss and membrane leakage were reduced in RAP2.6L overexpression plants under waterlogging stress. Time course analyses of ABA content and production of hydrogen peroxide (H2O2) showed that increased ABA precedes the increase of H2O2. It is also followed by a marked increase in the antioxidant enzyme activities. Increased ABA promoted stomatal closure and made leaves exhibit a delayed waterlogging induced premature senescence. Furthermore, RAP2.6L overexpression caused significant increases in the transcripts of antioxidant enzyme genes APX1 (ascorbate peroxidase 1) and FSD1 (Fe-superoxide dismutase 1), the ABA biosynthesis gene ABA1 (ABA deficient 1) and signaling gene ABH1 (ABA-hypersensitive 1) and the waterlogging responsive gene ADH1 (alcohol dehydrogenase 1), while the transcript of ABI1 (ABA insensitive 1) was decreased. ABA inhibits seed germination and seedling growth and phenotype analysis showed that the integration of abi1-1 mutation into the RAP2.6L overexpression lines reduces ABA sensitivity. These suggest that RAP2.6L overexpression delays waterlogging induced premature senescence and might function through ABI1-mediated ABA signaling pathway.
KeywordsRAP2.6L ABA Waterlogging Stomatal closure Antioxidant enzyme activity ABA signaling
This study was supported by Key Basic Scientific Study and Development Plan (973 plan; grant no. 2012CB114003) and Natural Science Foundation (grant no. 31171830) of China, and Jiangsu Provincial Priority Academic Program Development of Higher Education Institutions.
- Dörffling K, Dörffling H, Luck E (2009) Improved frost tolerance and winter hardiness in proline overaccumulating winter wheat mutants obtained by in vitro-selection is associated with increased carbohydrate, soluble protein and abscisic acid (ABA) levels. Euphytica 165(3):545–556CrossRefGoogle Scholar
- Obayashi T, Hayashi S, Saeki M, Ohta H, Kinoshita K (2009) ATTED-II provides coexpressed gene networks for Arabidopsis. Nucleic Acids Res 37(Database issue):D987–D991Google Scholar
- Strizhov N, Abraham E, krész L, Blickling S, Zilberstein A, Schell J, Koncz C, Szabados L (1997) Differential expression of two P5CS genes controlling proline accumulation during salt-stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis. Plant J 12(3):557–569PubMedCrossRefGoogle Scholar