Disease relevance of ESP

• A 43 kDa protein with ESP activity and sequence homology to the ESP of Arabidopsis thaliana was cloned from the broccoli cv. Packman and expressed in Escherichia coli [1].
• In no-choice experiments, where larvae were confined on one or the other ecotype, weight gain was more rapid on Landsberg erecta than on Columbia. Genetic mapping of this difference in insect susceptibility using recombinant inbred lines resulted in the discovery of the TASTY locus near 85 cM on chromosome 1 of Arabidopsis [2].

High impact information on ESP

• A quantitative trait locus (QTL) on chromosome 3 epistatically affects nitrile formation in combination with ESP; this QTL has been termed EPITHIOSPECIFIER MODIFIER1 (ESM1) [3].
• The heterologously expressed Arabidopsis ESP was able to convert glucosinolates both to epithionitriles and to simple nitriles in the presence of myrosinase, and thus it was more versatile than previously described ESPs [4].
• The Arabidopsis epithiospecifier protein promotes the hydrolysis of glucosinolates to nitriles and influences Trichoplusia ni herbivory [4].
• The TASTY locus on chromosome 1 of Arabidopsis affects feeding of the insect herbivore Trichoplusia ni [2].
• The TASTY locus is distinct from known genetic differences between Columbia and Landsberg erecta that affect glucosinolate content, trichome density, disease resistance, and flowering time [2].

Biological context of ESP

• This observation suggests that ESP is likely to be involved in jasmonate-mediated defence and disease resistance mechanisms [5].
• 3. The amino acid sequence of several tryptic peptides of ESP (accounting for about 50% of the total sequence) made it possible to establish the high similarity (81% identity) with a hypothetical 37 kDa protein (TrEMBL data base accession number Q39104) and several jasmonate-inducible proteins from Arabidopsis thaliana [5].

Associations of ESP with chemical compounds

• Genetic manipulation designed to attenuate or eliminate expression of ESP in broccoli could increase the fractional conversion of glucoraphanin to sulforaphane, enhancing potential health benefits [1].
• Nitrile formation in vitro however does not require ESP but only the presence of Fe(II) and myrosinase [6].
• A significant loss of ESP activity paralleled the decrease in sulforaphane nitrile formation [7].

Other interactions of ESP

• The four early-induced genes in opr3 encode lipoxygenase, a putative bHLH transcription factor, epithiospecifier protein and an unknown protein [8].
• Pathogen resistance was not altered in WRKY53 overexpressors or knockouts (W53-KO), suggesting that ESR has a greater impact on WRKY53 function in senescence than WRKY53 on ESR function in pathogen resistance [9].

Analytical, diagnostic and therapeutic context of ESP

• ESP was isolated from Brassica napus seeds by anionic exchange and gel filtration chromatography [5].

References