Novel Mutant Alleles Reveal a Role of the Extra-Large G Protein in Rice Grain Filling, Panicle Architecture, Plant Growth, and Disease Resistance

Plant growth and grain filling are the key agronomical traits for grain weight and yield of rice. The continuous improvement in rice yield is required for a future sustainable global economy and food security. The heterotrimeric G protein complex containing a canonical α subunit (RGA1) couples extracellular signals perceived by receptors to modulate cell function including plant development and grain weight. We hypothesized that, besides RGA1, three atypical, extra-large GTP-binding protein (XLG) subunits also regulate panicle architecture, plant growth, development, grain weight, and disease resistance. Here, we identified a role of XLGs in agronomic traits and stress tolerance by genetically ablating all three rice XLGs individually and in combination using the CRISPR/Cas9 genome editing in rice. For this study, eight (three single, two double, and three triple) null mutants were selected. Three XLG proteins combinatorically regulate seed filling, because loss confers a decrease in grain weight from 14% with loss of one XLG and loss of three to 32% decrease in grain weight. Null mutations in XLG2 and XLG4 increase grain size. The mutants showed significantly reduced panicle length and number per plant including lesser number of grains per panicle compared to the controls. Loss-of-function of all individual XLGs contributed to 9% more aerial biomass compared to wild type (WT). The double mutant showed improved salinity tolerance. Moreover, loss of the XLG gene family confers hypersensitivity to pathogens. Our findings suggest that the non-canonical XLGs play important roles in regulating rice plant growth, grain filling, panicle phenotype, stress tolerance, and disease resistance. Genetic manipulation of XLGs has the potential to improve agronomic properties in rice.

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Essential Role of Sugar Transporter OsSWEET11 During the Early Stage of Rice Grain Filling

Plant and Cell Physiology ◽

10.1093/pcp/pcx040 ◽

2017 ◽

Vol 58 (5) ◽

pp. 863-873 ◽

Cited By ~ 46

Author(s):

Lai Ma ◽

Dechun Zhang ◽

Qisong Miao ◽

Jing Yang ◽

Yuanhu Xuan ◽

...

Keyword(s):

Essential Role ◽

Early Stage ◽

Grain Filling ◽

Rice Grain ◽

Sugar Transporter

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The GT factor ZmGT-3b mediates growth–defense tradeoff by regulating photosynthesis and defense response1

10.1101/2021.03.12.435151 ◽

2021 ◽

Author(s):

Qianqian Zhang ◽

E Lizhu ◽

Weixing Dai ◽

Mingliang Xu ◽

Jianrong Ye

Keyword(s):

Disease Resistance ◽

Plant Growth ◽

Induced Defense ◽

Light Responses ◽

Transcriptional Reprogramming ◽

Development Face ◽

Temporal And Spatial ◽

Upregulated Genes ◽

Wall Components

AbstractPlant growth and development face constant threat from various environmental stresses. Transcription factors (TFs) are crucial for maintaining balance between plant growth and defense. Trihelix TFs display multifaceted functions in plant growth, development, and responses to various biotic and abiotic stresses. Here, we explore the role of a trihelix TF, ZmGT-3b, in regulating the growth–defense tradeoff in maize (Zea mays). ZmGT-3b is primed for instant response to Fusarium graminearum challenge by implementing a rapid and significant reduction of its expression to suppress seedling growth and enhance disease resistance. ZmGT-3b knockdown led to diminished growth, but improved disease resistance and drought tolerance in maize seedlings. In ZmGT-3b knockdown seedlings, the chlorophyll content and net photosynthetic rate were strongly reduced, whereas the contents of major cell wall components, such as lignin, were synchronically increased. Correspondingly, ZmGT-3b knockdown specifically downregulated photosynthesis-related genes, especially ZmHY5 (encoding a conserved central regulator of seedling development and light responses), but synchronically upregulated genes associated with secondary metabolite biosynthesis and defense-related functions. ZmGT-3b knockdown induced defense-related transcriptional reprogramming and increased biosynthesis of lignin without immune activation. These data suggest that ZmGT-3b is a regulator of plant growth–defense tradeoff that coordinates metabolism during growth-to-defense transitions by optimizing the temporal and spatial expression of photosynthesis- and defense-related genes.One-sentence summaryZmGT-3b regulates photosynthesis activity and synchronically suppresses defense response.

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Role of the endogenous fungal metabolites in the plant growth improvement and stress tolerance

Fungi Bio-Prospects in Sustainable Agriculture, Environment and Nano-technology ◽

10.1016/b978-0-12-821734-4.00002-2 ◽

2021 ◽

pp. 381-401

Author(s):

Pooja Sharma ◽

Surendra Pratap Singh

Keyword(s):

Plant Growth ◽

Stress Tolerance ◽

Fungal Metabolites

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New thoughts on the role of the βγ subunit in G protein signal transduction

Biochemistry and Cell Biology ◽

10.1139/o00-075 ◽

2000 ◽

Vol 78 (5) ◽

pp. 537-550 ◽

Cited By ~ 1

Author(s):

Barbara Vanderbeld ◽

Gregory M Kelly

Keyword(s):

Signal Transduction ◽

G Protein ◽

G Proteins ◽

G Protein Coupled Receptors ◽

Limited Information ◽

Α Subunit ◽

Downstream Effectors ◽

Receptor Signal ◽

G Protein Coupled

Heterotrimeric G proteins are involved in numerous biological processes, where they mediate signal transduction from agonist-bound G-protein-coupled receptors to a variety of intracellular effector molecules and ion channels. G proteins consist of two signaling moieties: a GTP-bound α subunit and a βγ heterodimer. The βγ dimer, recently credited as a significant modulator of G-protein-mediated cellular responses, is postulated to be a major determinant of signaling fidelity between G-protein-coupled receptors and downstream effectors. In this review we have focused on the role of βγ signaling and have included examples to demonstrate the heterogeneity in the heterodimer composition and its implications in signaling fidelity. We also present an overview of some of the effectors regulated by βγ and draw attention to the fact that, although G proteins and their associated receptors play an instrumental role in development, there is rather limited information on βγ signaling in embryogenesis.Key words: G protein, βγ subunit, G-protein-coupled receptor, signal transduction, adenylyl cyclase.

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Calcium Application Enhances Drought Stress Tolerance in Sugar Beet and Promotes Plant Biomass and Beetroot Sucrose Concentration

International Journal of Molecular Sciences ◽

10.3390/ijms20153777 ◽

2019 ◽

Vol 20 (15) ◽

pp. 3777 ◽

Cited By ~ 6

Author(s):

Seyed Abdollah Hosseini ◽

Elise Réthoré ◽

Sylvain Pluchon ◽

Nusrat Ali ◽

Bastien Billiot ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Sugar Beet ◽

Stress Tolerance ◽

Mineral Nutrition ◽

Stress Responses ◽

Foliar Application ◽

Sucrose Concentration ◽

Drought Stress Tolerance

Numerous studies have demonstrated the potential of sugar beet to lose the final sugar yield under water limiting regime. Ample evidences have revealed the important role of mineral nutrition in increasing plant tolerance to abiotic stresses. Despite the vital role of calcium (Ca2+) in plant growth and development, as well as in stress responses as an intracellular messenger, its role in alleviating drought stress in sugar beet has been rarely addressed. Here, an attempt was undertaken to investigate whether, and to what extent, foliar application of Ca2+ confers drought stress tolerance in sugar beet plants exposed to drought stress. To achieve this goal, sugar beet plants, which were grown in a high throughput phenotyping platform, were sprayed with Ca2+ and submitted to drought stress. The results showed that foliar application of Ca2+ increased the level of magnesium and silicon in the leaves, promoted plant growth, height, and leaf coverage area as well as chlorophyll level. Ca2+, in turn, increased the carbohydrate levels in leaves under drought condition and regulated transcriptionally the genes involved in sucrose transport (BvSUC3 and BvTST3). Subsequently, Ca2+ enhanced the root biomass and simultaneously led to induction of root (BvSUC3 and BvTST1) sucrose transporters which eventually supported the loading of more sucrose into beetroot under drought stress. Metabolite analysis revealed that the beneficial effect of Ca2+ in tolerance to drought induced-oxidative stress is most likely mediated by higher glutathione pools, increased levels of free polyamine putrescine (Put), and lower levels of amino acid gamma-aminobutyric acid (GABA). Taken together, this work demonstrates that foliar application of Ca2+ is a promising fertilization strategy to improve mineral nutrition efficiency, sugar metabolism, redox state, and thus, drought stress tolerance.

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Sugar starvation-regulated MYBS2 and 14-3-3 protein interactions enhance plant growth, stress tolerance, and grain weight in rice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1904818116 ◽

2019 ◽

Vol 116 (43) ◽

pp. 21925-21935 ◽

Cited By ~ 10

Author(s):

Yi-Shih Chen ◽

Tuan-Hua David Ho ◽

Lihong Liu ◽

Ding Hua Lee ◽

Chun-Hua Lee ◽

...

Keyword(s):

Gene Expression ◽

Plant Growth ◽

Stress Tolerance ◽

Protein Interactions ◽

Nuclear Export ◽

Crop Improvement ◽

Growth Stress ◽

Grain Weight ◽

Sugar Starvation ◽

Key Enzyme

Autotrophic plants have evolved distinctive mechanisms for maintaining a range of homeostatic states for sugars. The on/off switch of reversible gene expression by sugar starvation/provision represents one of the major mechanisms by which sugar levels are maintained, but the details remain unclear. α-Amylase (αAmy) is the key enzyme for hydrolyzing starch into sugars for plant growth, and it is induced by sugar starvation and repressed by sugar provision. αAmy can also be induced by various other stresses, but the physiological significance is unclear. Here, we reveal that the on/off switch of αAmy expression is regulated by 2 MYB transcription factors competing for the same promoter element. MYBS1 promotes αAmy expression under sugar starvation, whereas MYBS2 represses it. Sugar starvation promotes nuclear import of MYBS1 and nuclear export of MYBS2, whereas sugar provision has the opposite effects. Phosphorylation of MYBS2 at distinct serine residues plays important roles in regulating its sugar-dependent nucleocytoplasmic shuttling and maintenance in cytoplasm by 14-3-3 proteins. Moreover, dehydration, heat, and osmotic stress repress MYBS2 expression, thereby inducing αAmy3. Importantly, activation of αAmy3 and suppression of MYBS2 enhances plant growth, stress tolerance, and total grain weight per plant in rice. Our findings reveal insights into a unique regulatory mechanism for an on/off switch of reversible gene expression in maintaining sugar homeostatic states, which tightly regulates plant growth and development, and also highlight MYBS2 and αAmy3 as potential targets for crop improvement.

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Role of G-proteins in the differentiation of epiphyseal chondrocytes

Journal of Molecular Endocrinology ◽

10.1530/jme-14-0093 ◽

2014 ◽

Vol 53 (2) ◽

pp. R39-R45 ◽

Cited By ~ 14

Author(s):

Andrei S Chagin ◽

Henry M Kronenberg

Keyword(s):

G Protein ◽

G Proteins ◽

Growth Plate ◽

Current Knowledge ◽

Postnatal Growth ◽

Chondrocyte Differentiation ◽

Growth Plate Chondrocytes ◽

Α Subunit ◽

G Protein Coupled

Herein, we review the regulation of differentiation of the growth plate chondrocytes by G-proteins. In connection with this, we summarize the current knowledge regarding each family of G-protein α subunit, specifically, Gαs, Gαq/11, Gα12/13, and Gαi/o. We discuss different mechanisms involved in chondrocyte differentiation downstream of G-proteins and different G-protein-coupled receptors (GPCRs) activating G-proteins in the epiphyseal chondrocytes. We conclude that among all G-proteins and GPCRs expressed by chondrocytes, Gαshas the most important role and prevents premature chondrocyte differentiation. Receptor for parathyroid hormone (PTHR1) appears to be the major activator of Gαsin chondrocytes and ablation of either one leads to accelerated chondrocyte differentiation, premature fusion of the postnatal growth plate, and ultimately short stature.

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Response of phytohormone homeostasis to heat stress and the roles of phytohormones in rice grain yield: a review

10.7287/peerj.preprints.27843 ◽

2019 ◽

Author(s):

Chao Wu ◽

She Tang ◽

Ganghua Li ◽

Shaohua Wang ◽

Shah Fahad ◽

...

Keyword(s):

Heat Stress ◽

Grain Yield ◽

Grain Filling ◽

Reproductive Organs ◽

Reproductive Stage ◽

Grain Weight ◽

Rice Grain ◽

Vascular Bundles ◽

Rice Varieties ◽

Heat Effects

Rice is highly susceptible to heat stress at the reproductive stage. In this review, we first summarize recent progress in heat effects on rice grain yield during different reproductive stages. Different responses of yield traits of rice to heat stress during different reproductive stages are identified. The number of spikelets per panicle is reduced by heat stress during the early reproductive stage but is not affected by heat stress during the mid-late reproductive stage. Spikelet sterility induced by heat stress can be attributed primarily to physiological abnormalities in the reproductive organs during flowering but attributed to structural and morphological abnormalities in reproductive organs during panicle initiation. The lower grain weight caused by heat stress during the early reproductive stage was due to a reduction in non-structural carbohydrates, undeveloped vascular bundles, and a reduction in grain length and width, while a shortened grain filling duration, reduced grain filling rate, and decreased grain width affect grain weight when heat stress occurs during grain filling. Phytohormones play vital roles in regulating plant adaptations against heat stress. We discuss the processes involving phytohormone homeostasis (biosynthesis, catabolism, deactivation, and transport) in response to heat stress. It is currently thought that biosynthesis and transport may be the key processes that determine phytohormone levels and final grain yield in rice under heat stress conditions. Finally, we prospect that screening and breeding rice varieties with comprehensive tolerance to heat stress throughout the entire reproductive phase could be feasible to cope with unpredictable heat events in the future. Studies in phytohormone homeostatic response are needed to further reveal the key processes that determine phytohormone levels under heat condition.

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