Different PIN-FORMED proteins (PINs) contribute to intercellular and intracellular auxin transport, depending on their distinctive subcellular localizations. Arabidopsis thaliana PINs with a long hydrophilic loop (HL) (PIN1 to PIN4 and PIN7; long PINs) localize predominantly to the plasma membrane (PM), whereas short PINs (PIN5 and PIN8) localize predominantly to internal compartments. However, the subcellular localization of the short PINs has been observed mostly for PINs ectopically expressed in different cell types, and the role of the HL in PIN trafficking remains unclear. Here, we tested whether a long PIN-HL can provide its original molecular cues to a short PIN by transplanting the HL. The transplanted long PIN2-HL was sufficient for phosphorylation and PM trafficking of the chimeric PIN5:PIN2-HL but failed to provide the characteristic polarity of PIN2. Unlike previous observations, PIN5 showed clear PM localization in diverse cell types where PIN5 is natively or ectopically expressed and even polar PM localization in one cell type. Furthermore, in the root epidermis, the subcellular localization of PIN5 switched from PM to internal compartments according to the developmental stage. Our results suggest that the long PIN-HL is partially modular for the trafficking behavior of PINs and that the intracellular trafficking of PIN is plastic depending on cell type and developmental stage.

Plants are immobile and, to overcome harsh environmental conditions such as drought, salt, and cold, they have evolved complex signaling pathways. Abscisic acid (ABA), an isoprenoid phytohormone, is a critical signaling mediator that regulates diverse biological processes in various organisms. Significant progress has been made in the determination and characterization of key ABA-mediated molecular factors involved in different stress responses, including stomatal closure and developmental processes, such as seed germination and bud dormancy. Since ABA signaling is a complex signaling network that integrates with other signaling pathways, the dissection of its intricate regulatory network is necessary to understand the function of essential regulatory genes involved in ABA signaling. In the present review, we focus on two aspects of ABA signaling. First, we examine the perception of the stress signal (abiotic and biotic) and the response network of ABA signaling components that transduce the signal to the downstream pathway to respond to stress tolerance, regulation of stomata, and ABA signaling component ubiquitination. Second, ABA signaling in plant development processes, such as lateral root growth regulation, seed germination, and flowering time regulation is investigated. Examining such diverse signal integration dynamics could enhance our understanding of the underlying genetic, biochemical, and molecular mechanisms of ABA signaling networks in plants. 592 2 of 20 and developmental stages, plants were experiencing drought stress [5,[9][10][11][12][13][14][15][16][17]. Therefore, ABA is a misnomer [18], even though it plays a role in leaf senescence and seed dormancy, potentially via osmotic effects [19][20][21]. It has been observed that drought-stressed vegetative tissues of numerous plants accumulate ABA (40-fold induction) within hours of osmotic stress and then it decreases after rehydration. In addition, ABA has been considered a long-distance stress signal between shoots and roots [22]. Therefore, the study of spatiotemporal expression of genes that control ABA metabolism's rate-limiting steps is essential for understanding how plants adapt to stress. Other than its role in adaptation to abiotic stress, ABA has been shown to be a key regulator of pathogen virulence [23][24][25][26][27], which could offer insights into the basis of the ABA-synthesizing ability of numerous bio-and necrotrophic microbes [24,[28][29][30].Gene products acting in the vicinity of the cell wall or at the interface of the plasma membrane/cytoskeleton/cell wall are considered the most likely elements to participate in initial stress perception. For instance, gated aquaporins (plasma membrane intrinsic proteins (PIPs)) and osmo-/ion channels at the cell wall-plasma membrane interface may be implicated in the upstream perception [31][32][33]. The receptor of ABA remained unknown until 2009. Before then, several ABA receptors had been reported [34][35][36][37][38][39][40]; however, further investigations did not substantiate any o...

In the current scenario of changing climatic conditions and the rising global population, there is an urgent need to explore novel, efficient, and economical natural products for the benefit of humankind. Biosurfactants are one of the latest explored microbial synthesized biomolecules that have been used in numerous fields, including agriculture, pharmaceuticals, cosmetics, food processing, and environment-cleaning industries, as a source of raw materials, for the lubrication, wetting, foaming, emulsions formulations, and as stabilizing dispersions. The amphiphilic nature of biosurfactants have shown to be a great advantage, distributing themselves into two immiscible surfaces by reducing the interfacial surface tension and increasing the solubility of hydrophobic compounds. Furthermore, their eco-friendly nature, low or even no toxic nature, durability at higher temperatures, and ability to withstand a wide range of pH fluctuations make microbial surfactants preferable compared to their chemical counterparts. Additionally, biosurfactants can obviate the oxidation flow by eliciting antioxidant properties, antimicrobial and anticancer activities, and drug delivery systems, further broadening their applicability in the food and pharmaceutical industries. Nowadays, biosurfactants have been broadly utilized to improve the soil quality by improving the concentration of trace elements and have either been mixed with pesticides or applied singly on the plant surfaces for plant disease management. In the present review, we summarize the latest research on microbial synthesized biosurfactant compounds, the limiting factors of biosurfactant production, their application in improving soil quality and plant disease management, and their use as antioxidant or antimicrobial compounds in the pharmaceutical industries.

Over the past few decades, plant genomics research has been studied extensively bringing about a revolution in the field of plant biotechnology. Molecular markers, useful for plant genome analysis, have now become an important tool in crop improvement. The development and use of molecular markers for the detection and exploitation of DNA polymorphism is one of the most significant developments in the field of molecular genetics. The presence of various types of molecular markers, and differences in their principles, methodologies and applications require careful consideration in choosing one or more of such methods. No molecular markers are available yet that fulfill all requirements needed by researchers. In this article we attempt to review most of the available DNA markers that can be routinely employed in various aspects of plant genome analysis such as characterization of genetic variability, genome fingerprinting, genome mapping, gene localization, analysis of genome evolution, population genetics, taxonomy, plant breeding, and diagnostics. The emerging patterns make up a unique feature of the analyzed individual and are currently considered to be the ultimate tool for biological individualization.