ABSTRACT
Isoprenoid compounds synthesised in the plastids are involved in plant response to water deficit. The functionality of the biosynthetic pathway of these compounds under drought stress has been analysed at the physiological and molecular levels in two related species of tomato (Solanum chilense and Solanum lycopersicum) that differ in their tolerance to abiotic challenge. Expression analysis of the genes encoding enzymes of these pathways (DXS, IPI, GGPPS, PSY1, NCED and HPT1) in plants at different RWC values shows significant differences for only GGPPS and HPT1, with higher expression in the tolerant S. chilense. Chlorophyll, carotenoids, α-tocopherol and ABA content was also determined in both species under different drought conditions. In agreement with HPT1 transcriptional activity, higher α-tocopherol content was observed in S. chilense than in S. lycopersicum, which correlates with a lower degree of lipoperoxidation in the former species. These results suggest that, in addition to lower stomatal conductance, α-tocopherol biosynthesis is part of the adaptation mechanisms of S. chilense to adverse environmental conditions.
Subject(s)
Dehydration/physiopathology , Plastids/metabolism , Solanum lycopersicum/genetics , Solanum lycopersicum/metabolism , alpha-Tocopherol/metabolism , Abscisic Acid/biosynthesis , Adaptation, Physiological , Carotenoids/biosynthesis , Chile , Chlorophyll/biosynthesis , Droughts , Gene Expression Regulation, Plant , Genes, Plant , Lipid Peroxidation , Solanum lycopersicum/growth & development , Plant Stomata/physiology , Plastids/genetics , Solanum/genetics , Solanum/metabolism , Terpenes/metabolism , Transcription, GeneticABSTRACT
Plants protect themselves against pests using their wide chemical defense arsenal. Among several defense proteins, proteinase inhibitors appear to be an important group. Proteinase inhibitors are widely present in plants and they are often found in storage organs. They are known to be inducible in plants by injuries, such as insect damage. Because these proteins inhibit digestive enzymes of insect larvae and microbial proteases, they may be considered as mechanisms to improve the plant defense against pests. In recent years, growing research on plant proteinase inhibitors has confirmed their important role in plant defense, although several aspects are still controversial. Although many plants have related proteinase inhibitors, which have been shown to affect metabolism and/or development of different insects, these plants do not seem to share a common inhibitor induction mechanism. This is an emerging field and much work is yet to be done.
Subject(s)
Ecology , Insecta , Plant Physiological Phenomena , Protease Inhibitors , AnimalsABSTRACT
Plants protect themselves against pests using their wide chemical defense arsenal. Among several defense proteins, proteinase inhibitors appear to be an important group. Proteinase inhibitors are widely present in plants and they are often found in storage organs. They are known to be inducible in plants by injuries, such as insect damage. Because these proteins inhibit digestive enzymes of insect larvae and microbial proteases, they may be considered as mechanisms to improve the plant defense against pests. In recent years, growing research on plant proteinase inhibitors has confirmed their important role in plant defense, although several aspects are still controversial. Although many plants have related proteinase inhibitors, which have been shown to affect metabolism and/or development of different insects, these plants do not seem to share a common inhibitor induction mechanism. This is an emerging field and much work is yet to be done
