Overexpression of the 3′(2′),5′-bisphosphate nucleotidase gene AtAHL confers enhanced resistance to Pectobacterium carotovorum in Arabidopsis

The Arabidopsis AtAHL gene encodes a 3′(2′),5′-bisphosphate nucleotidase that catalyzes the conversion of adenosine 3′,5′-bisphosphate (PAP) into adenosine monophosphate and inorganic phosphate. We have generated transgenic Arabidopsis overexpressing this gene under control of the cauliflower mosaic virus 35S (CaMV 35S) promoter. Transgenic lines integrating a single copy of the insert DNA and constitutively expressing the AtAHL gene were selected. The transgenic lines of Arabidopsis plants exhibited enhanced resistance to Pectobacterium carotovorum subsp. carotovorum . In general, plant defense responses and sulfur metabolism are linked through jasmonic acid signaling. The expression of sulfur-related defense genes is known to be induced via a jasmonate-mediated signaling pathway. In this work, we observed that the expression of AtAHL was also induced by jasmonate treatment in Arabidopsis . Our data suggest that PAP catabolic activity enhanced by the jasmonate signaling pathway contributes to the rapid flux of the sulfur activation pathway, accelerates the incorporation of activated sulfur into sulfur-containing defense molecules such as defensins, thionins, and glucosinolates, and thereby increases defense resistance in plants.