Search

In order to clarify the role of PnSS gene in regulating the terpenoid contents in tobacco, an overexpression vector of PnSS gene was constructed. Tobacco cultivar Basma 14 was transformed by the leaf disc method, and the tobacco plants with overexpression of PnSS gene were obtained. The contents (mass fractions) of aroma components in the transformed tobacco leaves were analyzed by HS-SPME-GC/MS. The results showed that: 1) The consistency between amino acid sequences of PnSS and homolog NtSS in tobacco were 81.9%. PnSS and NtSS contained squalene and phytoene synthase domains. 2) Overexpression of PnSS gene resulted in shorter tobacco plants and smaller leaves. Compared with roots and stalks, the relative expression level of PnSS gene in tobacco leaves was the highest. 3) Overexpression of PnSS gene increased the contents of i3 aroma components, including acetic acid, furfuryl alcohol, 4,6-dimethylpyrimidine, phenylacetaldehyde, 3,5-dimethylbenzaldehyde, diene nicotine, dihydroactinidiolide, 2-methylpyrazine, nonanoic acid, isovaleraldehyde, 2 methyl butyl aldehyde, cembrane and nicotine in tobacco leaves. The treatment decreased the contents of 7 aroma components, including 2,3-dihydro-3,5 dihydroxy-6-methyl-4 (H) -pyran-4-one, 2,3-bipyridine, phytol, phenylethanol, neophydiene, benzaldehyde and mesmin. Therefore, the overexpression of PnSS gene inhibited the growth and development of tobacco plants and changed the contents of aroma components, such as terpenoids, in tobacco leaves. [ABSTRACT FROM AUTHOR]

Transposable elements exist widely throughout plant genomes and play important roles in plant evolution. Auxin is an important regulator that is traditionally associated with root development and drought stress adaptation. The DEEPER ROOTING 1 (DRO1) gene is a key component of rice drought avoidance. Here, we identified a transposon that acts as an autonomous auxin‐responsive promoter and its presence at specific genome positions conveys physiological adaptations related to drought avoidance. Rice varieties with a high and auxin‐mediated transcription of DRO1 in the root tip show deeper and longer root phenotypes and are thus better adapted to drought. The INDITTO2 transposon contains an auxin response element and displays auxin‐responsive promoter activity; it is thus able to convey auxin regulation of transcription to genes in its proximity. In the rice Acuce, which displays DRO1‐mediated drought adaptation, the INDITTO2 transposon was found to be inserted at the promoter region of the DRO1 locus. Transgenesis‐based insertion of the INDITTO2 transposon into the DRO1 promoter of the non‐adapted rice variety Nipponbare was sufficient to promote its drought avoidance. Our data identify an example of how transposons can act as promoters and convey hormonal regulation to nearby loci, improving plant fitness in response to different abiotic stresses. Role of auxin regulating drought avoidance remains unclear. In this study, an INDITTO2 transposon inserted at a DRO1 locus conveys auxin‐regulated transcription of the DRO1 and thus enhances rice root drought avoidance. It shows that the interaction of transposon and auxin can improve plant fitness. [ABSTRACT FROM AUTHOR]