A Wound- and Methyl Jasmonate-Inducible Transcript Coding for a Myrosinase-Associated Protein with Similarities to an Early Nodulin

Abstract

Myrosinase is regarded as a defense-related enzyme in the Brassicaceae and is capable of hydrolyzing glucosinolates into various compounds, some of which are toxic. Severa1 myrosinase isoenzymes exist, and some of them have been found in association with nonmyrosinase proteins. One of these associated proteins, myrosinase-associated protein (MyAP), was purified from seeds of Brassica The myrosinase-glucosinolate system is a preformed, two-component system that is activated upon tissue damage, whereby enzymatic decomposition of glucosinolates by the myrosinase enzyme takes place. Glucosinolates and their hydrolysis products are claimed to function as a defense against generalized herbivores and are implicated as a factor in host-plant recognition by specialized consumers (Chew, 1988;Louda and Mole, 1991). Myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) consists of a group of isoenzymes capable of hydrolyzing the thioglucoside bond in glucosinolates. The resulting aglycones rearrange spontaneously and yield, in addition to sulfate, compounds such as isothiocyanates, organic thiocyanates, epithionitriles, and nitriles. Within individual plants of a species, several different types of glucosinolates exist. The exact outcome of the reaction depends on a number of factors '

Regulation of the Wound‐Induced Myrosinase‐Associated Protein Transcript in Brassica Napus Plants

“…20 pg each digest was separated by gel electrophoresis in an 0.7 % agarose gel and transferred to a Hybond N + membrane. The Southern filter was hybridized using either a probe corresponding to base pairs 275-1049 in iMyAP12 or base pairs 127-597 in MyAP4 (Taipalensuu et al, 1996). After each hybridization, the filter was washed twice at room temperature in 2XNaCI/Cit, 0.1 % SDS for 10 min, then for 15 min at 65°C with IXNaCIiCit, 0.1% SDS.…”

“…RNA was transferred to Hybond N+ (Amersham) or to positively charged nylon membranes from Boehringer Mannheim, according to the instructions of the manufacturers. The probes used for Northern hybridizations correspond to base pairs 1114-1221 in iMyAP9 and the corresponding region in the seed MyAP clone MyAP5 (Taipalensuu et al, 1996), 1089-1194. In this region, iMyAP9 and iMyAP12 share 95 % identical positions, while iMyAP9 and MyAP5 share only 60% identical positions.…”

“…cDNA clones encoding the inducible form of MyAP were isolated from a cDNA library representing mRNA from MeJA-induced B. nupus var. Hanna leaves using a B. nupus seed MyAP cDNA clone (Taipalensuu et al, 1996) as a probe. The cDNA library was produced by Clontech in the ?,ZAP I1 vector (Stratagene).…”

“…The cDNA library was produced by Clontech in the ?,ZAP I1 vector (Stratagene). For software to manage and analyze the sequences, see Taipalensuu et al (1996). The FASTA program (Pearson and Lipman, 1988) was used to search nucleic acid and protein databases and was accessed through the e-mail server on GenomeNet (Supercomputer Laboratory, Institute for Chemical Research, Kyoto University, Japan).…”

“…Several of the wound-induced genes have been demonstrated to respond to JAiMeJA (Hildmann et al, 1992;Reinbothe et at., '1994;Sembdner and Parthier, 1993;Taipalensuu et al, 1996). Furthermore, some of the wound-inducible transcripts also increase in amount in response to ABA, and ABA was found to be required for a functional wound response (Hildmann et al, 1992;PenaCortes et al, 1995).…”