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Adaptation to environmental changes is an important fitness trait for crop development. Photoperiod is an essential factor in seasonal control of flowering time. Sensing of day-length requires an interaction between the Photoperiod and the endogenous rhythms that is controlled by plant circadian clock. Thus, circadian clock is a critical regulator and internal molecular time-keeping mechanism, controlling key agricultural traits in crop plants such as the ability to adjust their growth and physiology to anticipate diurnal environmental changes. Here, we describe the gene Tomato Dof Daily Fluctuations 1 (TDDF1), which is involved in circadian regulation and stress resistance. Large daily oscillations in TDDF1 expression were retained after transferring to continuous dark (DD) or light (LL) conditions. Interestingly, overexpressing TDDF1 induce early flowering in tomato through up-regulation of the flowering-time control genes, moreover, by protein-protein interaction with the floral inducer SFT gene. Notably, overexpressing TDDF1 in tomato was associated with chlorophyll overaccumulation by up-regulating the related biosynthetic genes. TDDF1 expression results in improved drought, salt, various hormones stress tolerance alongwith resistance to late blight caused by Phytophthora infestans. This study can be a distinctive strategy to improve other economically important crops.

Salvia officinalis is one of the most important medicinal and aromatic plants in terms of nutritional and medicinal value because it contains a variety of vital active ingredients. Terpenoid compounds, particularly monoterpenes (C10) and sesquiterpenes, are the most important and abundant among these active substances (C15). Terpenes play a variety of roles and have beneficial biological properties in plants. With these considerations, the current study sought to clone theNAD+-dependent farnesol dehydrogenase (SoFLDH, EC: 1.1.1.354) gene from S. officinalis. Functional analysis revealed that, SoFLDH has an open reading frame of 2,580 base pairs that encodes 860 amino acids.SoFLDH has two conserved domains and four types of highly conserved motifs: YxxxK, RXR, RR (X8) W, TGxxGhaG. However, SoFLDH was cloned from Salvia officinalis leaves and functionally overexpressed in Arabidopsis thaliana to investigate its role in sesquiterpenoid synthases. In comparison to the transgenic plants, the wild-type plants showed a slight delay in growth and flowering formation. To this end, a gas chromatography-mass spectrometry analysis revealed that SoFLDH transgenic plants were responsible for numerous forms of terpene synthesis, particularly sesquiterpene. These results provide a base for further investigation on SoFLDH gene role and elucidating the regulatory mechanisms for sesquiterpene synthesis in S. offcinalis. And our study paves the way for the future metabolic engineering of the biosynthesis of useful terpene compounds in S. offcinalis.

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A constant supply of soil nutrients is critical for the normal growth and development of plants. However, most environments are unstable and this variability depends on numerous factors that include availability of water content, pH, redox potential, an abundance of organic matter as well as microorganisms in soils. To overcome these hurdles and to maintain nutritional homeostasis, plants have evolved sophisticated systems for the continuous provision of soil nutrients necessary for their uninterrupted growth. In this pressing scenario, plant microRNAs (miRNAs) have emerged as a central regulator of nutrients uptake and transport during limited nutrient conditions. Numerous studies establish the intrinsic involvement of miRNAs and their immediate targets facilitating the core mechanisms related to nutrient homeostasis. In this review, we focus on global overview of miRNAs and their dynamic roles involved in keeping nutritional balance within the plants mediated via post-transcriptional regulation by transcript cleavage or translational inhibition of their target mRNAs. In addition, we have also focused on some of the forefront plant adaptations mediated by miRNAs during nutrient deficiency, such as root architecture modifications, transport channel modulation, long distance signaling and subsequent nutrient mobilization through phloem. Moreover, plant strategy to bring out such alterations is a highly perplexing mechanism that requires changes at large scale which involves coordinated regulation of miRNAs and plant hormones at multiple levels. Deciphering the underlying miRNAs-based mechanisms for streamlining nutrient uptake and transport would be a giant step towards solving this conundrum.

Potato (Solanum tuberosum) late blight caused by oomycete Phytophthora infestans (Pi) is highly destructive to potato yield and cost huge losses each year. Regulation of a network of transcription machinery, controlled by transcription factors (TF's), is required to overcome the susceptibility. WRKY TF's are known to regulate transcription machinery upon biotic and abiotic stresses in different crop plants. We cloned and characterized a WRKY gene, StWRKY1, from potato cDNA synthesized from Pi infested leaves. StWRKY1 protein localized typically in the nucleus. Overexpression (OE) of StWRKY1 positively regulates Pi resistance as well as drought tolerance in transgenic potato. The elevated resistance in OE lines was co-related with higher accumulation of pathogenesis-related (PR) genes as compared to untransformed control plants. Interestingly, increased susceptibility of co-suppression (CSP) plants was associated with down regulation of PR genes expression. Moreover, transgenic lines overexpressing StWRKY1 showed tolerance in terms of less rate of water loss, during dehydration assay. Importantly, expression of StWRKY1 was upregulated upon treatment with plant hormones, suggesting its involvement in basal signal transduction pathway. Overall, our findings provided evidence that StWRKY1 positively regulate biotic and abiotic stress resistance thereby modulating plant basal defense networks, thus play a significant role for crop improvement.

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