SPS — Nicotiana attenuata

Summary

A4A49_61142 (SPS, also known as PMT3) in coyote tobacco (Nicotiana attenuata) encodes a protein with putrescine N-methyltransferase, spermidine synthase, and spermine synthase activities (EC 2.1.1.53). This gene is associated with polyamine, nicotine, and alkaloid metabolism, as well as responses to herbivores and insects. It is linked to primary growth, phloem loading, sucrose metabolism, starch breakdown, and electron transport chain processes. The encoded protein localizes to the cytosol, mitochondria, nucleus, and plasma membrane. Associations with traits include photosynthetic rate, respiration rate, starch and sucrose content, jasmonic acid content, and responses to high temperature, drought, and salt stress. The gene is also connected to disease tolerance, thermotolerance, and nematode susceptibility. Studies of related genes in other species link the family to fruit sweetness, starch concentration, chilling stress response, and saline-alkali tolerance.