Analysis of DNA fingerprint and polysaccharide constituent in Durian cultivars

Abstract

Polysaccharide Gel (PG) from fruit-rinds of durian (Durio zibethinus Merr.) is a pectic polysaccharide, according to prior studied, the polysaccharide exhibits antibacterial activity and immunomodulatory activity. PG have found to be useful for food and pharmaceutical applications such as jelly, tabet coating film dressing, antiseptic gel, PG teat dip for protecting bovine mastitis, etc. Interestingly, PG from durian cultivars, ‘Chani’ ‘Pauenmuang’ (native cultivar) and ‘Monthong’ from Chumporn province, have the different bactericidal potency. In this study aimed to characterize and identify the difference between durian cultivars and between cultivated areas in molecular level together with bioactive PG in fruit-rinds. The cultivated-durians, ‘Kradumthong’, ‘Monthong’ and ‘Chani’ from Chanthaburi province; ‘Pauenmuang’, ‘Monthong’ and ‘Chani’ from Chumporn province were investigated. The matK gene in chloroplast genome of these durians was 1,509 bp in length. In comparison with the previous reported in GenBank, accession no. AY321188. The matK of ‘Pauenmuang’ cultivar presented either adenosine or cytosine substitutions at the position 275, whereas ‘Monthong’ and ‘Chani’ cultivars from both provinces, and ‘Kradumthong’ from Chanthaburi province presented the cytosine substitutions at the same position as same as the previous reported in GenBank. The matK sequences of all tested durian cultivars were also found the cytosine and thymidine substitutions at the position 860 and 862, respectively. The results provided not enough information to characterize the variation of durian cultivars then the matK gene was not suitable to be used as the molecular marker for durian identification in this study. In addition, the preliminary RAPD study indicated that these durian cultivars exhibited genetic variation. The DNA profiles showed the specific patterns of different durian cultivars. The dendrogram was constructed by unweighted pair group method with arithmetic averages, UPGMA. Durian cultivars can be divided into two main groups, native planted ‘Pauenmuang’ and commercially cultivated (‘Monthong’, ‘Chani’ and ‘Kradumthong’). The results of PG analysis showed that PG analysis showed that PG of ‘Monthong’ fruit-rinds from both provinces gave the highest percentage of the total yield (P<0.05) and also the highest viscosity (P<0.05). The pH range of PG was 2.437-2.526. The important major sugar,galacturonic acid content, in PG from ‘Kradumthong’ cultivars was the highest. The results of the galacturonic acid content in PG was not significantly different (P>0.05) within the same cultivars, but significantly different (P<0.05) from different durian cultivars. The results suggested that The polymorphic band profiles of RAPD could be used as molecular marker for identification durian cultivars together with the galacturonic acid content in PG in durian-rinds.