Methylthioalkylmalate synthases: genetics, ecology and evolution

Abstract

Glucosinolates display an enormous amount of structural variation, both within and between species. This diversity is thought to have evolved in response to challenges imposed on plants by their biotic environment. During the past decade, glucosinolates and myrosinase-catalyzed glucosinolate hydrolysis have become excellent examples for understanding functional diversification in plant secondary metabolism and plant defence. Methylthioalkylmalate (MAM) synthase genes and enzymes are central to the diversification of aliphatic glucosinolate structures in Arabidopsis thaliana and related plants. This review summarizes efforts to elucidate how MAM-mediated diversity in aliphatic glucosinolate structures is generated and maintained. It also attempts to put variability in methionine carbon chain elongation during glucosinolate biosynthesis into an ecological and evolutionary context.

The Arabidopsis Thylakoid ADP/ATP Carrier TAAC Has an Additional Role in Supplying Plastidic Phosphoadenosine 5′-Phosphosulfate to the Cytosol

“…Note that the amounts of GS were much higher in Ws-4 than corresponding GS in Col-0, which is in agreement with differences in GS profiles of both ecotypes as reported previously (Kliebenstein et al, 2001). Exemplarily, the composition of aliphatic GS in Ws-4 and Col-0 is known to result from different alleles at the MAM locus determining the production of various aliphatic GS with different carbon chain lengths (Kroymann et al, , 2003Benderoth et al, 2009) Interestingly, papst1-1 and papst1-2 plants accumulated desulfo-precursors of indolic GS despite no differences in the levels of mature metabolites. The observed amount of desulfo-GS precursors in the mutant plants was severalfold higher than would correspond to unused substrates and is thus indicative for stimulated GS biosynthesis.…”

A feedback insensitive isopropylmalate synthase affects acylsugar composition in cultivated and wild tomato

“…5B), leads to a dramatic shift in acylsugar acyl chain composition in S. pennellii accessions (Supplemental Table S5). This is analogous to the situation with MAM alleles, including loss-of-function variants, which influence the types of Met-derived glucosinolates found in Arabidopsis accessions (Kroymann et al, 2003;Benderoth et al, 2009).…”

“…Phylogenetic relationships between IPMS and MAM sequences from different species. Sequences were aligned using MUSCLE (Edgar, 2004) and used for phylogenetic reconstruction using the method noted by Benderoth et al (2009). Specifically, the tree was constructed with Mr. Bayes version 3.2.1 using the wag model (Huelsenbeck and Ronquist, 2001).…”

“…Only the values for the internal branches are shown. The tree was rooted using the Ostreococcus tauri (Ot) IPMS sequence, based on previous knowledge from Benderoth et al (2009). At, Arabidopsis; Bd, Boechera divaricarpa; Bi, Brassica insularis; Bo, Brassica oleracea; Ca, Capsicum annuum; Nb, N. benthamiana; Os, Oryza sativa; Pt, Populus trichocarpa; Sl, S. lycopersicum; Sopen, S. pennellii; Zm, Zea mays.…”

“…For phylogenetic reconstruction of IPMS and MAM sequences, we combined information from two sources. First, we obtained the MAM and IPMS sequences used in a previous study (Benderoth et al, 2009). Second, we obtained homologous sequences in Nicotiana benthamiana, Capsicum annuum, and Solanum tuberosum using a BLAST search with E , 1e-10.…”