Wheat (<i>Triticum aestivum</i>) peptide (s) mimic gibberellin action and regulate stomatal opening

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="metricconverter"> Wheat peptides (0.5 to 3 KDa M_r) mimick hormonal activity like that of gibberellins and forced open dark closed stomata. The deionized amphoteric peptides solution after passing through cation and anion exchanger resins was run through Amicon’s ultrafilters, 10, 3 and 0.5 kDa (M_r) cut off system. The 3 to 0.5 kDa fraction passed through sephadex LH-20 column and collected in 140 tubes (5 ml in each tube). The two fractions F 9 (91-100 tubes) and F 12 (121-130) were found much active on stomatal opening and <img src='/image/spc_char/alpha.gif' border=0>-amylase activity, respectively and were ninhydrin positive. Capillary electrophoresis of F 9 fraction yielded several peptides ranging 1600 to 2200 (M_r) and F 12 fraction showed 1800 – 2800(M_r). Both the fractions were totally hydrolysed for amino acid analysis by HPLC. Most of the amino acids were present except cystein in both the fractions. The F 9 fraction, (peptide present in 10 μg fresh wt tissue per ml) induced the dark grown closed stomata to open upto 70%. In F 12 fraction, (peptide present in 10 μg fresh wt equivalent tissue per ml) showed <img src='/image/spc_char/alpha.gif' border=0>-amylase induction which was much higher than GA₃(10^{-9 <i style="">M</i>}). The peptide might be present in membrane and bound with GA that activated <img src='/image/spc_char/alpha.gif' border=0>-amylase m-RNA synthesis. The peptide might act directly on <img src='/image/spc_char/alpha.gif' border=0>-amylase gene. </smarttagtype>