-
1.
Research advances of MYB transcription factors in plant stress resistance and breeding.
Li, J, Han, G, Sun, C, Sui, N
Plant signaling & behavior. 2019;(8):1613131
-
-
Free full text
-
Abstract
Plants face various stresses during the growth and development processes. The specific transcription factors bind to the cis-acting elements upstream of the stress resistance genes, specifically regulating the expression of the gene in plants and increasing the adaptability of plants to environmental stress. The transcription factor-mediated gene expression regulatory networks play an important role in plant stress response pathways. MYB (v-myb avian myeloblastosis viral oncogene homolog) transcription factor is one of the largest members of the transcription factor family in plants. It participates and has a great influence on all aspects of plant growth and development. It plays an important role in plant secondary metabolic regulation, hormone and environmental factor responses, cell differentiation, organ morphogenesis, and cell cycle regulation. This review mainly introduces the characteristics, structure, and classification of MYB transcription factors, as well as the abiotic stress resistance to drought, salt, temperature, and other functions in breeding, and provides a reference for the research and utilization of transcription factors in the future.
-
2.
Topology of TROL protein in thylakoid membranes of Arabidopsis thaliana.
Vojta, L, Fulgosi, H
Physiologia plantarum. 2019;(1):300-308
Abstract
Thylakoid rhodanase-like protein (TROL) is a nuclear-encoded protein of thylakoid membranes required for tethering of ferredoxin:nicotinamide adenine dinucleotide phosphate (NADPH) oxydoreductase (FNR). It has been proposed that the dynamic interaction of TROL with flavoenzyme FNR, influenced by environmental light conditions, regulates the fate of photosynthetic electrons, directing them either to NADPH synthesis or to other acceptors, including reactive oxygen species detoxification pathways. Inside the chloroplasts, TROL has a dual localization: an inner membrane precursor form and a thylakoid membrane mature form, which has been confirmed by several large-scale chloroplast proteomics studies, as well as protein import experiments. Unlike the localization, the topology of TROL in the membranes, which is a prerequisite for further studies of its properties and function, has not been experimentally confirmed yet. Thermolysin was proven to be a valuable protease to probe the surface of chloroplasts and membranes in general. By treating the total chloroplast membranes using increasing protease concentration, sequential degradation of TROL was observed, indicating protected polypeptides of TROL and possible domain orientation. To further substantiate the obtained results, TROL-overexpressing Arabidopsis line (OX) and line in which the central rhodanase-like domain (RHO) has been partially deleted (ΔRHO), were used as well. While OX line showed the same degradation pattern of TROL as the wild-type, surprisingly, TROL from ΔRHO membranes was not detectable even at the lowest protease concentration applied, indicating the importance of this domain to the integrity of TROL. In conclusion, TROL is a polytopic protein with a stroma-exposed C-terminal FNR-binding region, and the thylakoid lumen-located RHO domain.
-
3.
Tackling Plant Phosphate Starvation by the Roots.
Crombez, H, Motte, H, Beeckman, T
Developmental cell. 2019;(5):599-615
Abstract
Plant responses to phosphate deprivation encompass a wide range of strategies, varying from altering root system architecture, entering symbiotic interactions to excreting root exudates for phosphorous release, and recycling of internal phosphate. These processes are tightly controlled by a complex network of proteins that are specifically upregulated upon phosphate starvation. Although the different effects of phosphate starvation have been intensely studied, the full extent of its contribution to altered root system architecture remains unclear. In this review, we focus on the effect of phosphate starvation on the developmental processes that shape the plant root system and their underlying molecular pathways.
-
4.
PIN2 Polarity Establishment in Arabidopsis in the Absence of an Intact Cytoskeleton.
Glanc, M, Fendrych, M, Friml, J
Biomolecules. 2019;(6)
Abstract
Cell polarity is crucial for the coordinated development of all multicellular organisms. In plants, this is exemplified by the PIN-FORMED (PIN) efflux carriers of the phytohormone auxin: The polar subcellular localization of the PINs is instructive to the directional intercellular auxin transport, and thus to a plethora of auxin-regulated growth and developmental processes. Despite its importance, the regulation of PIN polar subcellular localization remains poorly understood. Here, we have employed advanced live-cell imaging techniques to study the roles of microtubules and actin microfilaments in the establishment of apical polar localization of PIN2 in the epidermis of the Arabidopsis root meristem. We report that apical PIN2 polarity requires neither intact actin microfilaments nor microtubules, suggesting that the primary spatial cue for polar PIN distribution is likely independent of cytoskeleton-guided endomembrane trafficking.
-
5.
Mitochondrial Pyruvate Dehydrogenase Contributes to Auxin-Regulated Organ Development.
Ohbayashi, I, Huang, S, Fukaki, H, Song, X, Sun, S, Morita, MT, Tasaka, M, Millar, AH, Furutani, M
Plant physiology. 2019;(2):896-909
-
-
Free full text
-
Abstract
Pyruvate dehydrogenase is the first enzyme (E1) of the PDH complex (PDC). This multienzyme complex contains E1, E2, and E3 components and controls the entry of carbon into the mitochondrial tricarboxylic acid cycle to enable cellular energy production. The E1 component of the PDC is composed of an E1α catalytic subunit and an E1β regulatory subunit. In Arabidopsis (Arabidopsis thaliana), there are two mitochondrial E1α homologs encoded by IAA-CONJUGATE-RESISTANT 4 (IAR4) and IAR4-LIKE (IAR4L), and one mitochondrial E1β homolog. Although IAR4 was reported to be involved in auxin conjugate sensitivity and auxin homeostasis in root development, its precise role remains unknown. Here, we provide experimental evidence that mitochondrial PDC E1 contributes to polar auxin transport during organ development. We performed genetic screens for factors involved in cotyledon development and identified an uncharacterized mutant, macchi-bou 1 (mab1). MAB1 encodes a mitochondrial PDC E1β subunit that can form both a homodimer and a heterodimer with IAR4. The mab1 mutation impaired MAB1 homodimerization, reduced the abundance of IAR4 and IAR4L, weakened PDC enzymatic activity, and diminished mitochondrial respiration. A metabolomics analysis showed significant changes in metabolites including amino acids in mab1 and, in particular, identified an accumulation of Ala. These results suggest that MAB1 is a component of the Arabidopsis mitochondrial PDC E1. Furthermore, in mab1 mutants and seedlings where the TCA cycle was pharmacologically blocked, we found reduced abundance of the PIN-FORMED (PIN) auxin efflux carriers, possibly due to impaired PIN recycling and enhanced PIN degradation in vacuoles. Therefore, we suggest that mab1 induces defective polar auxin transport via metabolic abnormalities.
-
6.
Arabidopsis acyl-CoA-binding proteins regulate the synthesis of lipid signals.
Lung, SC, Chye, ML
The New phytologist. 2019;(1):113-117
Abstract
Plant lipid signals are crucial developmental modulators and stress response mediators. A family of acyl-CoA-binding proteins (ACBPs) participates in the lipid trafficking of these signals. Isoform-specific functions can arise from differences in their subcellular distribution, tissue-specificity, stress-responsiveness, and ligand selectivity. In lipid-mediated cell signaling, plant ACBPs are not merely transporters but are also important regulators via their interaction with lipid-metabolic enzymes and precursor lipids. In this Insight, the regulatory roles of plant ACBPs in the synthesis of various signaling lipids, including phosphatidic acid, sterols, oxylipins, and sphingolipids, are reviewed. We focus on the functional significance of these lipid signals in plant development and stress responses with an overview of recent work using reverse genetics and transgenic Arabidopsis.
-
7.
Spatiotemporal dynamics of a reaction-diffusion model of pollen tube tip growth.
Tian, C, Shi, Q, Cui, X, Guo, J, Yang, Z, Shi, J
Journal of mathematical biology. 2019;(4):1319-1355
Abstract
A reaction-diffusion model is proposed to describe the mechanisms underlying the spatial distributions of ROP1 and calcium on the pollen tube tip. The model assumes that the plasma membrane ROP1 activates itself through positive feedback loop, while the cytosolic calcium ions inhibit ROP1 via a negative feedback loop. Furthermore it is proposed that lateral movement of molecules on the plasma membrane are depicted by diffusion. It is shown that bistable or oscillatory dynamics could exist even in the non-spatial model, and stationary and oscillatory spatiotemporal patterns are found in the full spatial model which resemble the experimental data of pollen tube tip growth.
-
8.
The alternative splicing of SKU5-Similar3 in Arabidopsis.
Zhou, K
Plant signaling & behavior. 2019;(10):e1651182
-
-
Free full text
-
Abstract
Alternative splicing largely enhanced the diversity of transcriptome and proteome in eukaryas. Along with technological development, more and more genes are reported to be alternatively spliced during mRNA maturation. Here, I report the alternative splicing of SKU5-Similar 3 (SKS3) and its special splicing site in Arabidopsis. SKS3 was predicted to be alternatively transcribed into two variants, SKS3.1 and SKS3.2, which encoded a GPI-anchored protein and a soluble secretory protein, respectively. But, according to experimental data, instead of SKS3.2, a novel variant, SKS3.3, which encodes a protein with a transmembrane region at its C-terminus, was demonstrated. Interestingly, it exhibites a different organ-specific expression pattern with SKS3.1, and an unusual intron splicing site not following 'GT-AG' rule or any reported rule.
-
9.
A role for the auxin precursor anthranilic acid in root gravitropism via regulation of PIN-FORMED protein polarity and relocalisation in Arabidopsis.
Doyle, SM, Rigal, A, Grones, P, Karady, M, Barange, DK, Majda, M, Pařízková, B, Karampelias, M, Zwiewka, M, Pěnčík, A, et al
The New phytologist. 2019;(3):1420-1432
Abstract
distribution of auxin within plant tissues is of great importance for developmental plasticity, including root gravitropic growth. Auxin flow is directed by the subcellular polar distribution and dynamic relocalisation of auxin transporters such as the PIN-FORMED (PIN) efflux carriers, which can be influenced by the main natural plant auxin indole-3-acetic acid (IAA). Anthranilic acid (AA) is an important early precursor of IAA and previously published studies with AA analogues have suggested that AA may also regulate PIN localisation. Using Arabidopsis thaliana as a model species, we studied an AA-deficient mutant displaying agravitropic root growth, treated seedlings with AA and AA analogues and transformed lines to over-produce AA while inhibiting its conversion to downstream IAA precursors. We showed that AA rescues root gravitropic growth in the AA-deficient mutant at concentrations that do not rescue IAA levels. Overproduction of AA affects root gravitropism without affecting IAA levels. Treatments with, or deficiency in, AA result in defects in PIN polarity and gravistimulus-induced PIN relocalisation in root cells. Our results revealed a previously unknown role for AA in the regulation of PIN subcellular localisation and dynamics involved in root gravitropism, which is independent of its better known role in IAA biosynthesis.
-
10.
Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots.
Waidmann, S, Ruiz Rosquete, M, Schöller, M, Sarkel, E, Lindner, H, LaRue, T, Petřík, I, Dünser, K, Martopawiro, S, Sasidharan, R, et al
Nature communications. 2019;(1):3540
Abstract
Directional organ growth allows the plant root system to strategically cover its surroundings. Intercellular auxin transport is aligned with the gravity vector in the primary root tips, facilitating downward organ bending at the lower root flank. Here we show that cytokinin signaling functions as a lateral root specific anti-gravitropic component, promoting the radial distribution of the root system. We performed a genome-wide association study and reveal that signal peptide processing of Cytokinin Oxidase 2 (CKX2) affects its enzymatic activity and, thereby, determines the degradation of cytokinins in natural Arabidopsis thaliana accessions. Cytokinin signaling interferes with growth at the upper lateral root flank and thereby prevents downward bending. Our interdisciplinary approach proposes that two phytohormonal cues at opposite organ flanks counterbalance each other's negative impact on growth, suppressing organ growth towards gravity and allow for radial expansion of the root system.