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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A metabolic pathway assembled by enzyme selection may support herbivory of leaf-cutter ants on plant starch

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Author(s):
Bacci, Jr., Mauricio [1] ; Bueno, Odair Correa [2] ; Rodrigues, Andre [1] ; Pagnocca, Fernando Carlos [1] ; Somera, Alexandre Favarin [1] ; Silva, Aline
Total Authors: 6
Affiliation:
[1] Univ Estadual Paulista, Inst Biociencias Rio Clara, Ctr Estudos Insetos Sociais, Dept Bioquim & Microbiol, Sao Paulo - Brazil
[2] Univ Estadual Paulista, Inst Biociencias Rio Clara, Ctr Estudos Insetos Sociais, Dept Biol, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: JOURNAL OF INSECT PHYSIOLOGY; v. 59, n. 5, p. 525-531, MAY 2013.
Web of Science Citations: 11
Abstract

Mutualistic associations shape the evolution in different organism groups. The association between the leaf-cutter ant Atta sexdens and the basidiomycete fungus Leucoagaricus gongylophorus has enabled them to degrade starch from plant material generating glucose, which is a major food source for both mutualists. Starch degradation is promoted by enzymes contained in the fecal fluid that ants deposit on the fungus culture in cut leaves inside the nests. To understand the dynamics of starch degradation in ant nests, we purified and characterized starch degrading enzymes from the ant fecal fluid and from laboratory cultures of L. gongylophorus and found that the ants intestine positively selects fungal alpha-amylase and a maltase likely produced by the ants, as a negative selection is imposed to fungal maltase and ant alpha-amylases. Selected enzymes are more resistant to catabolic repression by glucose and proposed to structure a metabolic pathway in which the fungal alpha-amylase initiates starch catalysis to generate byproducts which are sequentially degraded by the maltase to produce glucose. The pathway is responsible for effective degradation of starch and proposed to represent a major evolutionary innovation enabling efficient starch assimilation from plant material by leaf-cutters. (c) 2013 Elsevier Ltd. All rights reserved. (AU)