Background: In recent decade, researchers aim to exploit the growth regulators from
natural sources due to adverse effects posed by chemical fertilizers. Ash gourd waste (peel and
seeds) has been traditionally used as a green manure for increasing the soil nutrients. The role of acetoin,
a major aroma compound of ash gourd (Benincasa hispida), and its glucosidic precursor as a
plant growth promoter was investigated in the present study.
Methods: Tobacco leaf discs exhibited growth when treated with methanolic extract of ash gourd.
The structure of active principal responsible for growth promoting activity was elucidated. Identification
of differentially expressed protein in response to treatment was also carried out.
Results: Free acetoin and its glucoside at a concentration of 0.44 μg/mL were found to enhance the
growth of tobacco (Nicotiana tabacum)
leaf discs by 44% and 56%, respectively, when grown in MS
medium. Two dimensional gel electrophoresis of the proteins isolated from the untreated and acetoin
glucoside treated tobacco leaf discs revealed the upregulation of a new protein in the treated samples.
This was identified as a Ras related nuclear GTPase or Ran protein, a very important regulatory
protein, by peptide mass finger printing. The physiological role of acetoin and its glucosidic precursor
present in ash gourd as a plant growth promoter is reported here for the first time.
Conclusion: The present study demonstrates growth promoting activity of acetoin and its glucoside.
The treatment of plants with such highly active but cheap chemicals could have potential use in increasing