Regulation and function of extracellular invertase from higher plants in relation to assimilate partitioning, stress responses and sugar signalling

2000 ◽  
Vol 27 (9) ◽  
pp. 815 ◽  
Author(s):  
Thomas Roitsch ◽  
Rainer Ehneß ◽  
Marc Goetz ◽  
Bettina Hause ◽  
Markus Hofmann ◽  
...  
Keyword(s):  
Stress Responses ◽  
Higher Plants ◽  
Assimilate Transport ◽  
Signal Molecules ◽  
Assimilate Partitioning ◽  
Long Distance ◽  
Phloem Unloading ◽  
Intracellular Location ◽  
Carbohydrate Partitioning ◽  
Extracellular Invertase

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 Carbohydrates are synthesised in photosynthetically active source tissues and exported, in most species in the form of sucrose, to photosynthetically less active or inactive sink tissues. Sucrose hydrolysis at the site of utilisation contributes to phloem unloading. This phenomenon links sink metabolism with phloem transport to, and partitioning between, sinks. Invertases catalyse the irreversible hydrolysis of sucrose and thus are expected to contribute to carbohydrate partitioning. Different invertase isoenzymes may be distinguished based on their intracellular location, their isoelectric points and pH optima. Extracellular, cell-wall-bound invertase is uniquely positioned to supply carbohydrates to sink tissues via an apoplasmic pathway, and links the transport sugar sucrose to hexose transporters. A number of studies demonstrate an essential function of this invertase isoenzyme for phloem unloading, carbohydrate partitioning and growth of sink tissues. Extracellular invertases were shown to be specifically expressed under conditions that require a high carbohydrate supply to sink tissues. Further, their expression is upregulated by a number of stimuli that affect source–sink relations. Substrate and reaction products of invertases are not only nutri-ents, but also signal molecules. Like hormones and in combination with hormones and other stimuli, they can regu-late many aspects of plant development from gene expression to long-distance nutrient allocation. Based on studies in Chenopodium rubrum, tomato (Lycopersicon esculentum) and tobacco (Nicotiana tabacum), the regulation of extracellular invertase and its function in assimilate partitioning, defence reactions and sugar signal transduction pathways are discussed.

scholarly journals Receptor-Like Protein Kinases Function Upstream of MAPKs in Regulating Plant Development

2020 ◽  
Vol 21 (20) ◽  
pp. 7638
Author(s):  
Zhe Wang ◽  
Xiaoping Gou
Keyword(s):  
Protein Kinases ◽  
Plant Development ◽  
Stress Responses ◽  
Higher Plants ◽  
Signal Molecules ◽  
Signal Pathways ◽  
Downstream Signaling ◽  
Mapk Cascades ◽  
Growth Development ◽  
Upstream Regulators

Mitogen-activated protein kinases (MAPKs) are a group of protein kinase broadly involved in various signal pathways in eukaryotes. In plants, MAPK cascades regulate growth, development, stress responses and immunity by perceiving signals from the upstream regulators and transmitting the phosphorylation signals to the downstream signaling components. To reveal the interactions between MAPK cascades and their upstream regulators is important for understanding the functional mechanisms of MAPKs in the life span of higher plants. Typical receptor-like protein kinases (RLKs) are plasma membrane-located to perceive endogenous or exogenous signal molecules in regulating plant growth, development and immunity. MAPK cascades bridge the extracellular signals and intracellular transcription factors in many RLK-mediated signaling pathways. This review focuses on the current findings that RLKs regulate plant development through MAPK cascades and discusses questions that are worth investigating in the near future.

scholarly journals Genome-Wide Identification and Expression Analysis of Sugar Transporter (ST) Gene Family in Longan (Dimocarpus longan L.)

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 342 ◽  
Author(s):  
Ting Fang ◽  
Yuan Peng ◽  
Ya Rao ◽  
Shenghao Li ◽  
Lihui Zeng
Keyword(s):  
Higher Plants ◽  
Expression Profiles ◽  
Pcr Analysis ◽  
Sugar Accumulation ◽  
Signal Molecules ◽  
Sugar Transporter ◽  
Flower Bud ◽  
Long Distance ◽  
Sugar Transporters ◽  
Dimocarpus Longan

Carbohydrates are nutrients and important signal molecules in higher plants. Sugar transporters (ST) play important role not only in long-distance transport of sugar, but also in sugar accumulations in sink cells. Longan (Dimocarpus longan L.) is one of the most important commercial tropical/subtropical evergreen fruit species in Southeast Asia. In this study, a total of 52 longan sugar transporter (DlST) genes were identified and they were divided into eight clades according to phylogenetic analysis. Out of these 52 DlST genes, many plant hormones (e.g., MeJA and gibberellin), abiotic (e.g., cold and drought), and biotic stress responsive element exist in their promoter region. Gene structure analysis exhibited that each of the clades have closely associated gene architectural features based on similar number or length of exons. The numbers of DlSTs, which exhibited alternative splicing (AS) events, in flower bud is more than that in other tissues. Expression profile analysis revealed that ten DlST members may regulate longan flowerbud differentiation. In silico expression profiles in nine longan organs indicated that some DlST genes were tissue specificity and further qRT-PCR analysis suggested that the transcript level of seven DlSTs (DlINT3, DlpGlcT1, DlpGlcT2, DlPLT4, DlSTP1, DlVGT1 and DlVGT2) was consistent with sugar accumulation in fruit, indicating that they might be involved in sugar accumulations during longan fruit development. Our findings will contribute to a better understanding of sugar transporters in woody plant.

scholarly journals Coding of Non-coding RNA: Insights Into the Regulatory Functions of Pri-MicroRNA-Encoded Peptides in Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Yi Ren ◽  
Yue Song ◽  
Lipeng Zhang ◽  
Dinghan Guo ◽  
Juan He ◽  
...  
Keyword(s):  
Stress Responses ◽  
Messenger Rna ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Regulatory Peptides ◽  
Open Reading Frames ◽  
Circular Rnas ◽  
Signal Molecules ◽  
Long Distance ◽  
Functional Peptides

Peptides composed of a short chain of amino acids can play significant roles in plant growth, development, and stress responses. Most of these functional peptides are derived by either processing precursor proteins or direct translation of small open reading frames present in the genome and sometimes located in the untranslated region sequence of a messenger RNA. Generally, canonical peptides serve as local signal molecules mediating short- or long-distance intercellular communication. Also, they are commonly used as ligands perceived by an associated receptor, triggering cellular signaling transduction. In recent years, increasing pieces of evidence from studies in both plants and animals have revealed that peptides are also encoded by RNAs currently defined as non-coding RNAs (ncRNAs), including long ncRNAs, circular RNAs, and primary microRNAs. Primary microRNAs (miRNAs) have been reported to encode regulatory peptides in Arabidopsis, grapevine, soybean, and Medicago, called miRNA-encoded peptides (miPEPs). Remarkably, overexpression or exogenous applications of miPEPs specifically increase the expression level of their corresponding miRNAs by enhancing the transcription of the MIRNA (MIR) genes. Here, we first outline the current knowledge regarding the coding of putative ncRNAs. Notably, we review in detail the limited studies available regarding the translation of miPEPs and their relevant regulatory mechanisms. Furthermore, we discuss the potential cellular and molecular mechanisms in which miPEPs might be involved in plants and raise problems that needed to be solved.

scholarly journals Phloem unloading via the apoplastic pathway is essential for shoot distribution of root-synthesized cytokinins

2021 ◽  
Author(s):  
Jiangzhe Zhao ◽  
Bingli Ding ◽  
Engao Zhu ◽  
Xiaojuan Deng ◽  
Mengyuan Zhang ◽  
...  
Keyword(s):  
Stress Responses ◽  
Wild Type ◽  
Long Distance ◽  
Phloem Unloading ◽  
Systemic Signaling ◽  
Xylem Loading ◽  
Growth Development ◽  
Low Levels ◽  
Apoplastic Pathway ◽  
Leaf Apoplast

Abstract Root-synthesized cytokinins are transported to the shoot and regulate the growth, development, and stress responses of aerial tissues. Previous studies have demonstrated that Arabidopsis (Arabidopsis thaliana) ATP binding cassette (ABC) transporter G family member 14 (AtABCG14) participates in xylem loading of root-synthesized cytokinins. However, the mechanism by which these root-derived cytokinins are distributed in the shoot remains unclear. Here, we revealed that AtABCG14-mediated phloem unloading through the apoplastic pathway is required for the appropriate shoot distribution of root-synthesized cytokinins in Arabidopsis. Wild-type rootstocks grafted to atabcg14 scions successfully restored trans-zeatin xylem loading. However, only low levels of root-synthesized cytokinins and induced shoot signaling were rescued. Reciprocal grafting and tissue-specific genetic complementation demonstrated that AtABCG14 disruption in the shoot considerably increased the retention of root-synthesized cytokinins in the phloem and substantially impaired their distribution in the leaf apoplast. The translocation of root-synthesized cytokinins from the xylem to the phloem and the subsequent unloading from the phloem are required for the shoot distribution and long-distance shootward transport of root-synthesized cytokinins. This study revealed a mechanism by which the phloem regulates systemic signaling of xylem-mediated transport of root-synthesized cytokinins from the root to the shoot.

scholarly journals A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 372
Author(s):  
Ekaterina Sukhova ◽  
Elena Akinchits ◽  
Sergey V. Gudkov ◽  
Roman Y. Pishchalnikov ◽  
Vladimir Vodeneev ◽  
...  
Keyword(s):  
Higher Plants ◽  
Initial Point ◽  
Electrical Signal ◽  
Terminal Point ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Variation Potential ◽  
Damaged Zone ◽  
Pressure Dynamics ◽  
The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

scholarly journals Impact of clock-associated Arabidopsis pseudo-response regulators in metabolic coordination

2009 ◽  
Vol 106 (17) ◽  
pp. 7251-7256 ◽  
Author(s):  
Atsushi Fukushima ◽  
Miyako Kusano ◽  
Norihito Nakamichi ◽  
Makoto Kobayashi ◽  
Naomi Hayashi ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Stress Responses ◽  
Clock Genes ◽  
Higher Plants ◽  
Tricarboxylic Acid Cycle ◽  
Integrated Analysis ◽  
Response Regulators ◽  
Triple Mutant ◽  
Mitochondrial Functions ◽  
Wide Range

In higher plants, the circadian clock controls a wide range of cellular processes such as photosynthesis and stress responses. Understanding metabolic changes in arrhythmic plants and determining output-related function of clock genes would help in elucidating circadian-clock mechanisms underlying plant growth and development. In this work, we investigated physiological relevance of PSEUDO-RESPONSE REGULATORS (PRR 9, 7, and 5) in Arabidopsis thaliana by transcriptomic and metabolomic analyses. Metabolite profiling using gas chromatography–time-of-flight mass spectrometry demonstrated well-differentiated metabolite phenotypes of seven mutants, including two arrhythmic plants with similar morphology, a PRR 9, 7, and 5 triple mutant and a CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1)-overexpressor line. Despite different light and time conditions, the triple mutant exhibited a dramatic increase in intermediates in the tricarboxylic acid cycle. This suggests that proteins PRR 9, 7, and 5 are involved in maintaining mitochondrial homeostasis. Integrated analysis of transcriptomics and metabolomics revealed that PRR 9, 7, and 5 negatively regulate the biosynthetic pathways of chlorophyll, carotenoid and abscisic acid, and α-tocopherol, highlighting them as additional outputs of pseudo-response regulators. These findings indicated that mitochondrial functions are coupled with the circadian system in plants.

scholarly journals A unique AtSar1D-AtRabD2a nexus modulates autophagosome biogenesis in Arabidopsis thaliana

2021 ◽  
Vol 118 (17) ◽  
pp. e2021293118
Author(s):  
Yonglun Zeng ◽  
Baiying Li ◽  
Changyang Ji ◽  
Lei Feng ◽  
Fangfang Niu ◽  
...  
Keyword(s):  
Stress Responses ◽  
Higher Plants ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Secretory Proteins ◽  
Insertion Mutant ◽  
Intermediate Metabolites ◽  
Dna Insertion ◽  
Autophagy Pathway ◽  
Copii Vesicles

In eukaryotes, secretory proteins traffic from the endoplasmic reticulum (ER) to the Golgi apparatus via coat protein complex II (COPII) vesicles. Intriguingly, during nutrient starvation, the COPII machinery acts constructively as a membrane source for autophagosomes during autophagy to maintain cellular homeostasis by recycling intermediate metabolites. In higher plants, essential roles of autophagy have been implicated in plant development and stress responses. Nonetheless, the membrane sources of autophagosomes, especially the participation of the COPII machinery in the autophagic pathway and autophagosome biogenesis, remains elusive in plants. Here, we provided evidence in support of a novel role of a specific Sar1 homolog AtSar1d in plant autophagy in concert with a unique Rab1/Ypt1 homolog AtRabD2a. First, proteomic analysis of the plant ATG (autophagy-related gene) interactome uncovered the mechanistic connections between ATG machinery and specific COPII components including AtSar1d and Sec23s, while a dominant negative mutant of AtSar1d exhibited distinct inhibition on YFP-ATG8 vacuolar degradation upon autophagic induction. Second, a transfer DNA insertion mutant of AtSar1d displayed starvation-related phenotypes. Third, AtSar1d regulated autophagosome progression through specific recognition of ATG8e by a noncanonical motif. Fourth, we demonstrated that a plant-unique Rab1/Ypt1 homolog AtRabD2a coordinates with AtSar1d to function as the molecular switch in mediating the COPII functions in the autophagy pathway. AtRabD2a appears to be essential for bridging the specific AtSar1d-positive COPII vesicles to the autophagy initiation complex and therefore contributes to autophagosome formation in plants. Taken together, we identified a plant-specific nexus of AtSar1d-AtRabD2a in regulating autophagosome biogenesis.

Sign in / Sign up

Export Citation Format

Share Document