-
1.
Crosstalk with Jasmonic Acid Integrates Multiple Responses in Plant Development.
Jang, G, Yoon, Y, Choi, YD
International journal of molecular sciences. 2020;(1)
Abstract
To date, extensive studies have identified many classes of hormones in plants and revealed the specific, nonredundant signaling pathways for each hormone. However, plant hormone functions largely overlap in many aspects of plant development and environmental responses, suggesting that studying the crosstalk among plant hormones is key to understanding hormonal responses in plants. The phytohormone jasmonic acid (JA) is deeply involved in the regulation of plant responses to biotic and abiotic stresses. In addition, a growing number of studies suggest that JA plays an essential role in the modulation of plant growth and development under stress conditions, and crosstalk between JA and other phytohormones involved in growth and development, such as gibberellic acid (GA), cytokinin, and auxin modulate various developmental processes. This review summarizes recent findings of JA crosstalk in the modulation of plant growth and development, focusing on JA-GA, JA-cytokinin, and JA-auxin crosstalk. The molecular mechanisms underlying this crosstalk are also discussed.
-
2.
Practical optimization of liquid chromatography/mass spectrometry conditions and pretreatment methods toward the sensitive quantification of auxin in plants.
Sugahara, K, Kitao, K, Yamagaki, T, Koyama, T
Rapid communications in mass spectrometry : RCM. 2020;(7):e8625
Abstract
RATIONALE The plant hormone auxin, indole-3-acetic acid, regulates many aspects of plant growth and development. Auxin quantification should offer broad insights into its mechanistic action in plants. However, limited auxin content in plant tissues hampers the establishment of quantification methods without the highest graded instruments or deeply specialized experimental techniques. METHODS In this study, we detailed optimized conditions for high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (LC/MS). We compared LC/MS conditions, such as columns, mobile phases, parameters of acquisition methods (selective or multiple ion monitoring), dwell times (DTs), and channel numbers, using differentially mixed authentic auxin and its related compounds. We further investigated pretreatment methods through the optimization of auxin recovery and irrelative compound removal from plant tissues prior to the LC/MS analysis. RESULTS Our LC/MS analysis demonstrated the particular importance of the column, DTs, and channel numbers on detection sensitivity. Our comparative analysis developed optimal pretreatment methods, including the pulverization of plants, concentration of extract through centrifugal evaporation, and removal of irrelative metabolites using liquid-liquid extraction and a spin filter. We injected plant samples into our LC/MS system, quantified auxin and eight related compounds in a single measurement, and determined the auxin increase in an auxin over-producing mutant. CONCLUSIONS Our practical optimization of LC/MS conditions and pretreatment methods provides detailed experimental processes toward the sensitive quantification of auxin from 10 mg of plant tissue. These processes have not always been clearly documented; therefore, our protocol could broadly contribute to technical advances in plant growth and development research.
-
3.
Brassinosteroids: Multidimensional Regulators of Plant Growth, Development, and Stress Responses.
Nolan, TM, Vukašinović, N, Liu, D, Russinova, E, Yin, Y
The Plant cell. 2020;(2):295-318
-
-
Free full text
-
Abstract
Brassinosteroids (BRs) are a group of polyhydroxylated plant steroid hormones that are crucial for many aspects of a plant's life. BRs were originally characterized for their function in cell elongation, but it is becoming clear that they play major roles in plant growth, development, and responses to several stresses such as extreme temperatures and drought. A BR signaling pathway from cell surface receptors to central transcription factors has been well characterized. Here, we summarize recent progress toward understanding the BR pathway, including BR perception and the molecular mechanisms of BR signaling. Next, we discuss the roles of BRs in development and stress responses. Finally, we show how knowledge of the BR pathway is being applied to manipulate the growth and stress responses of crops. These studies highlight the complex regulation of BR signaling, multiple points of crosstalk between BRs and other hormones or stress responses, and the finely tuned spatiotemporal regulation of BR signaling.
-
4.
The Anti-Senescence Activity of Cytokinin Arabinosides in Wheat and Arabidopsis Is Negatively Correlated with Ethylene Production.
Kučerová, Z, Rác, M, Mikulík, J, Plíhal, O, Pospíšil, P, Bryksová, M, Sedlářová, M, Doležal, K, Špundová, M
International journal of molecular sciences. 2020;(21)
Abstract
Leaf senescence, accompanied by chlorophyll breakdown, chloroplast degradation and inhibition of photosynthesis, can be suppressed by an exogenous application of cytokinins. Two aromatic cytokinin arabinosides (6-benzylamino-9-β-d-arabinofuranosylpurines; BAPAs), 3-hydroxy- (3OHBAPA) and 3-methoxy- (3MeOBAPA) derivatives, have recently been found to possess high anti-senescence activity. Interestingly, their effect on the maintenance of chlorophyll content and maximal quantum yield of photosystem II (PSII) in detached dark-adapted leaves differed quantitatively in wheat (Triticum aestivum L. cv. Aranka) and Arabidopsis (Arabidopsisthaliana L. (Col-0)). In this work, we have found that the anti-senescence effects of 3OHBAPA and 3MeOBAPA in wheat and Arabidopsis also differ in other parameters, including the maintenance of carotenoid content and chloroplasts, rate of reduction of primary electron acceptor of PSII (QA) as well as electron transport behind QA, and partitioning of absorbed light energy in light-adapted leaves. In wheat, 3OHBAPA had a higher protective effect than 3MeOBAPA, whereas in Arabidopsis, 3MeOBAPA was the more efficient derivative. We have found that the different anti-senescent activity of 3OHBAPA and 3MeOBAPA was coupled to different ethylene production in the treated leaves: the lower the ethylene production, the higher the anti-senescence activity. 3OHBAPA and 3MeOBAPA also efficiently protected the senescing leaves of wheat and Arabidopsis against oxidative damage induced by both H2O2 and high-light treatment, which could also be connected with the low level of ethylene production.
-
5.
The lipid code-dependent phosphoswitch PDK1-D6PK activates PIN-mediated auxin efflux in Arabidopsis.
Tan, S, Zhang, X, Kong, W, Yang, XL, Molnár, G, Vondráková, Z, Filepová, R, Petrášek, J, Friml, J, Xue, HW
Nature plants. 2020;(5):556-569
Abstract
Directional intercellular transport of the phytohormone auxin mediated by PIN-FORMED (PIN) efflux carriers has essential roles in both coordinating patterning processes and integrating multiple external cues by rapidly redirecting auxin fluxes. PIN activity is therefore regulated by multiple internal and external cues, for which the underlying molecular mechanisms are not fully elucidated. Here, we demonstrate that 3'-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1 (PDK1), which is conserved in plants and mammals, functions as a molecular hub that perceives upstream lipid signalling and modulates downstream substrate activity through phosphorylation. Using genetic analysis, we show that the loss-of-function Arabidopsis pdk1.1 pdk1.2 mutant exhibits a plethora of abnormalities in organogenesis and growth due to defective polar auxin transport. Further cellular and biochemical analyses reveal that PDK1 phosphorylates D6 protein kinase, a well-known upstream activator of PIN proteins. We uncover a lipid-dependent phosphorylation cascade that connects membrane-composition-based cellular signalling with plant growth and patterning by regulating morphogenetic auxin fluxes.
-
6.
Auxin-Abscisic Acid Interactions in Plant Growth and Development.
Emenecker, RJ, Strader, LC
Biomolecules. 2020;(2)
Abstract
Plant hormones regulate many aspects of plant growth, development, and response to biotic and abiotic stress. Much research has gone into our understanding of individual plant hormones, focusing primarily on their mechanisms of action and the processes that they regulate. However, recent research has begun to focus on a more complex problem; how various plant hormones work together to regulate growth and developmental processes. In this review, we focus on two phytohormones, abscisic acid (ABA) and auxin. We begin with brief overviews of the hormones individually, followed by in depth analyses of interactions between auxin and ABA, focusing on interactions in individual tissues and how these interactions are occurring where possible. Finally, we end with a brief discussion and future prospects for the field.
-
7.
Understanding the role of phytohormones in cotton fiber development through omic approaches; recent advances and future directions.
Wang, L, Wang, G, Long, L, Altunok, S, Feng, Z, Wang, D, Khawar, KM, Mujtaba, M
International journal of biological macromolecules. 2020;:1301-1313
Abstract
Cotton is among the most important fiber crops for the textile-based industry, thanks to its cellulose-rich mature fibers. The fiber initiation and elongation are one of the best models for deciphering mechanisms of single-cell differentiation and growth, that also target of fiber development programs. During the last couple of decades, high yielding omics approaches (genomics, transcriptomics, and proteomics), have helped in the identification of several genes and gene products involved in fiber development along with functional relationship to phytohormones. For example, MYB transcription factor family and Sus gene family have been evidenced by controlling cotton fiber initiation. Most importantly, the biosynthesis, responses, and transporting of phytohormones is documented to participate in the initiation of cotton fibers. Herein, in this review, the reliable genetic evidence by manipulating the above genes in cotton have been summarized to describe the relationships among key phytohormones, transcription factors, proteins, and downstream fiber growth-related genes such as Sus. The effect of other important factors such as ROS, fatty acid metabolism, and actin (globular multi-functional proteins) over fiber development has also been discussed. The challenges and deficiencies in the research of cotton fiber development have been mentioned along with a future perspective to discover new crucial genes using multiple omics analysis.
-
8.
Plant growth-regulating molecules as thermoprotectants: functional relevance and prospects for improving heat tolerance in food crops.
Sharma, L, Priya, M, Kaushal, N, Bhandhari, K, Chaudhary, S, Dhankher, OP, Prasad, PVV, Siddique, KHM, Nayyar, H
Journal of experimental botany. 2020;(2):569-594
Abstract
Among various abiotic stresses, heat stress is one of the most damaging, threatening plant productivity and survival all over the world. Warmer temperatures due to climatic anomalies above optimum growing temperatures have detrimental impacts on crop yield potential as well as plant distribution patterns. Heat stress affects overall plant metabolism in terms of physiology, biochemistry, and gene expression. Membrane damage, protein degradation, enzyme inactivation, and the accumulation of reactive oxygen species are some of the harmful effects of heat stress that cause injury to various cellular compartments. Although plants are equipped with various defense strategies to counteract these adversities, their defensive means are not sufficient to defend against the ever-rising temperatures. Hence, substantial yield losses have been observed in all crop species under heat stress. Here, we describe the involvement of various plant growth-regulators (PGRs) (hormones, polyamines, osmoprotectants, antioxidants, and other signaling molecules) in thermotolerance, through diverse cellular mechanisms that protect cells under heat stress. Several studies involving the exogenous application of PGRs to heat-stressed plants have demonstrated their role in imparting tolerance, suggesting the strong potential of these molecules in improving the performance of food crops grown under high temperature.
-
9.
Timing-dependent effects of salicylic acid treatment on phytohormonal changes, ROS regulation, and antioxidant defense in salinized barley (Hordeum vulgare L.).
Torun, H, Novák, O, Mikulík, J, Pěnčík, A, Strnad, M, Ayaz, FA
Scientific reports. 2020;(1):13886
Abstract
Cross-talk between exogenous salicylic acid (SA) and endogenous phytohormone pathways affects the antioxidant defense system and its response to salt stress. The study presented here investigated the effects of SA treatment before and during salt stress on the levels of endogenous plant growth regulators in three barley cultivars with different salinity tolerances: Hordeum vulgare L. cvs. Akhisar (sensitive), Erginel (moderate), and Kalaycı (tolerant). The cultivars' relative leaf water contents, growth parameters, proline contents, chlorophyll a/b ratios, and lipid peroxidation levels were measured, along with the activities of enzymes involved in detoxifying reactive oxygen species (ROS) including superoxide-dismutase, peroxidase, catalase, ascorbate-peroxidase, and glutathione-reductase. In addition, levels of several endogenous phytohormones (indole-3-acetic-acid, cytokinins, abscisic acid, jasmonic acid, and ethylene) were measured. Barley is known to be more salt tolerant than related plant species. Accordingly, none of the studied cultivars exhibited changes in membrane lipid peroxidation under salt stress. However, they responded differently to salt-stress with respect to their accumulation of phytohormones and antioxidant enzyme activity. The strongest and weakest increases in ABA and proline accumulation were observed in Kalaycı and Akhisar, respectively, suggesting that salt-stress was more effectively managed in Kalaycı. The effects of exogenous SA treatment depended on both the timing of the treatment and the cultivar to which it was applied. In general, however, where SA helped mitigate salt stress, it appeared to do so by increasing ROS scavenging capacity and antioxidant enzyme activity. SA treatment also induced changes in phytohormone levels, presumably as a consequence of SA-phytohormone salt-stress cross-talk.
-
10.
Genome-Wide Identification of the VQ Protein Gene Family of Tobacco (Nicotiana tabacum L.) and Analysis of Its Expression in Response to Phytohormones and Abiotic and Biotic Stresses.
Liu, C, Liu, H, Zhou, C, Timko, MP
Genes. 2020;(3)
Abstract
VQ motif-containing proteins (VQ proteins) are transcriptional regulators that work independently or in combination with other transcription factors (TFs) to control plant growth and development and responses to biotic and abiotic stresses. VQ proteins contain a conserved FxxhVQxhTG amino acid motif that is the main element of its interaction with WRKY TFs. We identified 59 members of the tobacco (Nicotiana tabacum L.) NtVQ gene family by in silico analysis and examined their differential expression in response to phytohormonal treatments and following exposure to biotic and abiotic stressors. NtVQ proteins clustered into eight groups based upon their amino acid sequence and presence of various conserved domains. Groups II, IV, V, VI, and VIII contained the largest proportion of NtVQ gene family members differentially expressed in response to one or more phytohormone, and NtVQ proteins with similar domain structures had similar patterns of response to different phytohormones. NtVQ genes differentially expressed in response to temperature alterations and mechanical wounding were also identified. Over half of the NtVQ genes were significantly induced in response to Ralstonia solanacearum infection. This first comprehensive characterization of the NtVQ genes in tobacco lays the foundation for further studies of the NtVQ-mediated regulatory network in plant growth, developmental, and stress-related processes.