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The flavin monooxygenases (FMO) encoded by plant YUCCA genes are thought to catalyze a rate-limiting step in the tryptamine pathway for indole-3-acetic acid biosynthesis. Recent experiments with different plant models have indicate that YUCCA genes play essential roles in growth and development through their contribution to the local pool of free auxin. In this study we have characterized five new genes that encode YUCCA-like FMOs in the tomato genome (ToFZY2 to ToFZY6), including gene structure, conserved motifs and phylogenetic analyses. As a first step towards clarifying the individual functions of ToFZY genes, we have used quantitative real-time RT-PCR to conduct a systematic comparison of the steady-state mRNA levels of 6 ToFZY genes, in 33 samples representing major organs and the entire tomato life cycle. We followed an absolute quantification strategy which allowed us to cross-compare transcript levels among different ToFZY genes in a given spatiotemporal coordinate. Our results indicate that expression of ToFZY genes is temporally and spatially regulated, and that the distinctive expression pattern of each ToFZY gene partially overlaps with other members of the multigenic family. We compare our data with previous results in other plant species and make some predictions about the role of tryptamine pathway in tomato growth and development.

The soilborne fungus Fusarium oxysporum f.sp. cubense is the causal agent of banana vascular wilt disease named Panama disease and one of the most serious threats to banana crops worldwide. A water-soluble addition compound of vitamin K3, menadione sodium bisulphite (MSB), first studied as a plant growth regulator, has recently been shown to induce resistance against Panama disease. Effective fungicides are not yet available to control this fatal disease. Here we report on two independent long-term experiments leading to the enhanced resistance response induced by MSB. The results demonstrated that MSB is an effective resistance activator in banana, and a potentially useful agent for the control of Panama disease.