MSc

The term „organic‟ is gaining more and more popularity these days. This
rapid growth may be traced to increased consumer confidence in organic foods as
well as to the concern about the possible health risks and environmental impacts
of inorganic food production methods. Even though the world carries so much of
perceptions regarding the quality of organic foods, the scientific backing is
missing for most of these assumptions. The study entitled „Proteome analysis of
organically grown yardlong bean [Vigna unguiculata sub sp. sesquipedalis (L.)
Verdcourt]‟ aimed at comparing organically and inorganically grown yardlong
beans in terms of protein and amino acid expression through 2-dimensional
proteome analysis (2DE).
Seeds of yardlong bean „Sharika‟ were sown, in plots each of 40 m 2 area.
The nutrient status of organic and inorganic plot was assessed prior to the study.
At two stages of crop growth i.e. at two months after sowing and four months
after sowing, immature pods were analysed for their nutrient status. Among the
pods of two plots, prominent variation was observed in the levels of iron and
manganese. In organoleptic analysis, 22 judges have evaluated the organic and
inorganic produce with a 9 point hedonic scale. Mann-Whitney test of these data
revealed that there is no significant difference between the organic and inorganic
produce.
Freshly harvested pods were used for the extraction of protein using
TCA/acetone buffer. This powdered sample was then solubilized in lysis buffer,
which was used for further analysis. Protein concentration was estimated using
Lowry‟s method. The samples with good quantity of protein for all the four
category .i.e, immature pods from inorganic and organic plot (C1 and C2) and
mature pods from inorganic and organic plot (C3 and C4), were subjected to
SDS-PAGE. Since there was no differential bands observed between pods from
inorganic and organic plot, the samples were subjected to 2DE. Eight differential
and two upregulated spots and one downregulated spot were identified whilecomparing the gels of inorganic and organic samples. These spots were then
excised and characterized using MALDI-ToF/MS through outsourcing. Data from
MALDI-ToF/MS was used as query for mascot search. Mascot search of some
spots yielded only hypothetical and uncharacterized proteins, so these proteins
were used as query for BLASTp and SmartBLAST analyses. Mascot results have
suggests that a protein, aldehyde dehydrogenase family 2 member C4-like, which
is involved in ferulic acid and sinapic acid biosynthesis, is present in the mature
pods from both the plots but is upregulated in organic produce. Another protein
trans-resveratrol di-O-methyltransferase-like is present in immature pods from
inorganic plot, which catalyses the biosynthesis of pterostilbene. Pterostilbene has
antifungal, antioxidant and pharmacological properties.
This study concludes that there is no significant difference in the
organoleptic properties between organic and inorganic produce and similarly there
is no much difference in the protein profile except that the inorganic produce
consisted of two proteins that are involved in biosynthesis of antioxidants,
whereas, in the organic produce, only one protein was identified to be involved in
the biosynthesis of antioxidants.