SPS — Nicotiana attenuata

Summary

A4A49_01601 (SPS, SPDE) on coyote tobacco chromosome 12 encodes a spermidine/spermine synthase with both spermidine synthase and spermine synthase activities (EC 2.5.1.16) and protein binding capability. The gene is associated with polyamine, spermidine, spermine, sucrose and UDP anabolism, starch breakdown, phloem loading, primary growth, flower development, electron transport chain, detoxification, homeostasis, defence response to bacteria, and virus-induced PTGS. The product localises to mitochondria, cytosol, plasmalemma, cytoplasm and nucleus. The gene has been connected to traits including photosynthetic rate, respiration rate, sucrose and starch content, jasmonic acid content, high temperature stress response, disease tolerance, salt tolerance, drought tolerance and thermotolerance, as well as nematode susceptibility, root growth inhibition, and resistance to Botrytis cinerea and Pseudomonas syringae. Studies of related genes in other species link it to polyamine metabolism, heat stress tolerance and cadaverine sensitivity.