Isolation and characterization of the MiCel1 gene from mango: ripening related expression and enhanced endoglucanase activity during softening
- 272 Downloads
Fruit ripening is characterized by the progressive depolymerisation of cell wall polysaccharides of which the cellulose/hemicellulose network forms an important component. We have cloned an endo-β-1,4-glucanase (EGase) homologue, MiCel1 from ripening mango (Mangifera indica var. Dashehari) that shows sequence similarity to higher plant EGase genes. The 2.3 kb cDNA of MiCel1 encodes a putative protein of 619 amino acids with a signal peptide that can direct it to cell walls. It also possesses a cellulose binding domain that is characteristic of microbial endoglucanases. Expression of MiCel1 is fruit specific and ripening related. There is a progressive increase in MiCel1 transcript accumulation during ripening that is correlated with increased EGase activity and associated with decrease in cellulose/hemicellulose content. In control (ethylene untreated) and 1-MCP treated fruit, ripening was delayed by around 3 days. This is associated with a delayed increase in MiCel1 expression and a delayed increase in EGase activity. It is proposed that expression of MiCel1 is closely associated with ripening and may play an important role in mango softening.
KeywordsEndo-β-1,4-glucanase Ethylene Fruit Mangifera indica Ripening 1-MCP
We are thankful to Central Institute for Subtropical Horticulture, Lucknow, for the mango samples. Senior Research Fellowship provided to Amita Chourasia by CSIR, India is gratefully acknowledged.
- Abu-Sarra AF, Abu-Goukh AA (1992) Changes in pectinesterase, polygalacturonase and cellulase activity during mango fruit ripening. J Hortic Sci 67:561–568Google Scholar
- Catala C, Bennett AB (1998) Cloning and sequence analysis of tomcel8; a new plant endo-beta-1,4-glucanase gene, encoding a protein with a putative carbohydrate binding domain (accession no. AF098292). Plant Physiol 118:1535Google Scholar
- Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F (1956) Colorimetric method for determination of sugars and related substances. Anal Biochem 28:350–356Google Scholar
- Rose JKC, Catala C, Brummell DA, Lashbrook CC, Gonzalez Bosch C, Bennett AB (1997) The tomato endo-beta-1,4-glucanase gene family: regulation by both ethylene and auxin. In: Kanellis A, Chang C, Kende H, Grierson D (eds) Biology and biotechnology of the plant hormone ethylene, vol 34. Kluwer Academic Publishers, Boston, pp 197–205Google Scholar
- Sambrook T, Fritsch EF, Maniatis T (1989) Molecular cloning: a laboratory manual. Cold Spring Harbour Laboratory Press, Cold Spring HarbourGoogle Scholar
- Trainotti L, Ferrarese F, Vecchia FD, Rascio N, Casadoro G (1999a) Two different endo-β-1,4-glucanase contribute to the softening of the strawberry fruits. J Plant Physiol 154:355–362Google Scholar