Expression of GhNAC2 from G. herbaceum, improves root growth and imparts tolerance to drought in transgenic cotton and Arabidopsis.
NAC proteins are plant-specific transcription factors that play essential roles in regulating development and responses to abiotic and biotic stresses. We show that over-expression of the cotton GhNAC2 under the CaMV35S promoter increases root growth in both Arabidopsis and cotton under unstressed conditions. Transgenic Arabidopsis plants also show improved root growth in presence of mannitol and NaCl while transgenic cotton expressing GhNAC2 show reduced leaf abscission and wilting upon water stress compared to control plants. Transgenic Arabidopsis plants also have larger leaves, higher seed number and size under well watered conditions, reduced transpiration and higher relative leaf water content. Micro-array analysis of transgenic plants over-expressing GhNAC2 reveals activation of the ABA/JA pathways and a suppression of the ethylene pathway at several levels to reduce expression of ERF6/ERF1/WRKY33/ MPK3/MKK9/ACS6 and their targets. This probably suppresses the ethylene-mediated inhibition of organ expansion, leading to larger leaves, better root growth and higher yields under unstressed conditions. Suppression of the ethylene pathway and activation of the ABA/JA pathways also primes the plant for improved stress tolerance by reduction in transpiration, greater stomatal control and suppression of growth retarding factors.
Plant Gene Expression Lab, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Samatha
S
Gunapati
Plant Gene Expression Lab, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Ram
R
Naresh
Dept. of Plant Physiology, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Sanjay
S
Ranjan
Dept. of Bioinformatics, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Deepti
D
Nigam
Plant tissue culture, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Aradhana
A
Hans
Plant tissue culture, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Praveen C
PC
Verma
Dept of Biochemistry, DeviAhilyaBai University, Indore-452001, India.
Rekha
R
Gadre
Dept. of Plant Physiology, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Uday V
UV
Pathre
Plant Gene Expression Lab, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Aniruddha P
AP
Sane
Plant Gene Expression Lab, CSIR- National Botanical Research Institute, Lucknow-226001, India.
Vidhu A
VA
Sane
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D055864:Droughts; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D018515:Plant Leaves / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000254:growth & development; D054712:Salinity; D015398:Signal Transduction; D012965:Sodium Chloride / Q000378:metabolism; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
D005030:Ethylenes; D010940:Plant Proteins; D014157:Transcription Factors; D012965:Sodium Chloride; C036216:ethylene