Effects of altered lignin biosynthesis on phenylpropanoid metabolism and plant stress
01 Nov 2013-Vol. 4, Iss: 6, pp 635-650
TL;DR: Examining and understanding the indirect effects of lignin modification on stress-related processes are essential, since they could ultimately impact the performance of low-lignin bioenergy feedstocks under agronomic field conditions.
Abstract: Modification of lignin in bioenergy feedstocks has become a common strategy to increase saccharification and biofuel yield. The lignin biosynthetic pathway in several plant species has been dissected and key enzymes have been manipulated in transgenic plants. Recent analyses of lignin-modified plants have shown that decreasing lignin biosynthesis can alter carbon flow within the phenylpropanoid pathway and indirectly affect the synthesis of other secondary metabolites, many of which can play important roles in plant–environment interactions. In addition, lignin modifications have also been shown to induce the expression of various stress response-related genes. Examining and understanding these indirect effects of lignin modification on stress-related processes are essential, since they could ultimately impact the performance of low-lignin bioenergy feedstocks under agronomic field conditions. Recent efforts to characterize such effects will be discussed in this review.
Citations
More filters
TL;DR: Recent proteomic studies on drought response in leaves are summarized to reveal the common and specialized drought-responsive mechanisms in different plants, providing new clues for understanding the molecular basis of plant drought tolerance.
Abstract: Plant drought tolerance is a complex trait that requires a global view to understand its underlying mechanism. The proteomic aspects of plant drought response have been extensively investigated in model plants, crops and wood plants. In this review, we summarize recent proteomic studies on drought response in leaves to reveal the common and specialized drought-responsive mechanisms in different plants. Although drought-responsive proteins exhibit various patterns depending on plant species, genotypes and stress intensity, proteomic analyses show that dominant changes occurred in sensing and signal transduction, reactive oxygen species scavenging, osmotic regulation, gene expression, protein synthesis/turnover, cell structure modulation, as well as carbohydrate and energy metabolism. In combination with physiological and molecular results, proteomic studies in leaves have helped to discover some potential proteins and/or metabolic pathways for drought tolerance. These findings provide new clues for understanding the molecular basis of plant drought tolerance.
194 citations
Cites background from "Effects of altered lignin biosynthe..."
...PAL catalyzes the transformation of phenylalanine to cinnamylate in the first step of lignin biosynthesis [172]....
[...]
TL;DR: Major advances in the basic understanding of the synthesis of the various wall polymers and its regulation has enabled strategies to alter the qualitative composition of wall materials, including a reduction/alteration of the lignin network to enhancepolysaccharide accessibility, reduction of polymer derived processing inhibitors, and increases in polysaccharides with a high hexose/pentose ratio.
175 citations
TL;DR: An assessment of the proteome within a broad time frame and during the different phenological stages may disclose the molecular mechanisms related to the developmental regulation of LT tolerance and facilitate the progress of genetically engineered stress-resistant plant varieties.
124 citations
TL;DR: A panel of novel genes and transcripts is found to be differentially expressed under salinity in Arg cultivar and a model is proposed for salt stress response in this salt tolerant cultivar of wheat employing the DEGs.
Abstract: Salt stress is one of the major adverse environmental factors limiting crop productivity. Considering Iran as one of the bread wheat origins, we sequenced root transcriptome of an Iranian salt tolerant cultivar, Arg, under salt stress to extend our knowledge of the molecular basis of salinity tolerance in Triticum aestivum. RNA sequencing resulted in more than 113 million reads and about 104013 genes were obtained, among which 26171 novel transcripts were identified. A comparison of abundances showed that 5128 genes were differentially expressed due to salt stress. The differentially expressed genes (DEGs) were annotated with Gene Ontology terms, and the key pathways were identified using Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway mapping. The DEGs could be classified into 227 KEGG pathways among which transporters, phenylpropanoid biosynthesis, transcription factors, glycosyltransferases, glutathione metabolism and plant hormone signal transduction represented the most significant pathways. Furthermore, the expression pattern of nine genes involved in salt stress response was compared between the salt tolerant (Arg) and susceptible (Moghan3) cultivars. A panel of novel genes and transcripts is found in this research to be differentially expressed under salinity in Arg cultivar and a model is proposed for salt stress response in this salt tolerant cultivar of wheat employing the DEGs. The achieved results can be beneficial for better understanding and improvement of salt tolerance in wheat.
58 citations
TL;DR: The results demonstrate the power of modifying the expression of an endogenous transcription factor to improve biofuel and biomass simultaneously, and also highlight the importance of field studies for “sorting” transgenic events.
Abstract: High biomass yields and minimal agronomic input requirements have made switchgrass, Panicum virgatum L., a leading candidate lignocellulosic bioenergy crop. Large-scale lignocellulosic biofuel production from such crops is limited by the difficulty to deconstruct cell walls into fermentable sugars: the recalcitrance problem. Our goal in this study was to assess the field performance of switchgrass plants overexpressing the switchgrass MYB4 (PvMYB4) transcription factor gene. PvMYB4 transgenic switchgrass can have great lignin reduction, which commensurately increases sugar release and biofuel production. Our results over two growing seasons showed that one transgenic event (out of eight) had important gains in both biofuel (32 % more) and biomass (63 % more) at the end of the second growing season relative to non-transgenic controls. These gains represent a doubling of biofuel production per hectare, which is the highest gain reported from any field-grown modified feedstock. In contrast to this transgenic event, which had relatively low ectopic overexpression of the transgene, five of the eight transgenic events planted did not survive the first field winter. The dead plants were all high-overexpressing events that performed well in the earlier greenhouse studies. Disease susceptibility was not compromised in any transgenic events over the field experiments. These results demonstrate the power of modifying the expression of an endogenous transcription factor to improve biofuel and biomass simultaneously, and also highlight the importance of field studies for “sorting” transgenic events. Further research is needed to develop strategies for fine-tuning temporal-spatial transgene expression in feedstocks to optimize desired phenotypes.
50 citations
Cites background from "Effects of altered lignin biosynthe..."
...There have been reports of enhanced resistance to pathogens in plants with modified lignin biosynthesis; the mechanisms are unclear but may be related to downstream effects of lignin suppression on the synthesis of defense-related compounds and/or defense signaling triggered by changes to cell wall integrity [37, 41]....
[...]
References
More filters
TL;DR: Limiting discussion to stress-induced phenylpropanoids eliminates few of the structural classes, because many compounds that are constitutive in one plant species or tissue can be induced by various stresses in another species or in another tissue of the same plant.
Abstract: Phenylpropanoid compounds encompass a wide range of structural classes and biological functions. Limiting discussion to stress-induced phenylpropanoids eliminates few of the structural classes, because many compounds thst are constitutive in one plant species or tissue can be induced by various stresses in another species or in another tissue of the same plant (Beggs et al., 1987; Christie et al., 1994).
4,046 citations
TL;DR: By cloning and characterizing an Arabidopsis defence-related gene (SID2) defined by mutation, it is shown that SA is synthesized from chorismate by means of ICS, and that SA made by this pathway is required for LAR and SAR responses.
Abstract: Salicylic acid (SA) mediates plant defences against pathogens, accumulating in both infected and distal leaves in response to pathogen attack. Pathogenesis-related gene expression and the synthesis of defensive compounds associated with both local and systemic acquired resistance (LAR and SAR) in plants require SA. In Arabidopsis, exogenous application of SA suffices to establish SAR, resulting in enhanced resistance to a variety of pathogens. However, despite its importance in plant defence against pathogens, SA biosynthesis is not well defined. Previous work has suggested that plants synthesize SA from phenylalanine; however, SA could still be produced when this pathway was inhibited, and the specific activity of radiolabelled SA in feeding experiments was often lower than expected. Some bacteria such as Pseudomonas aeruginosa synthesize SA using isochorismate synthase (ICS) and pyruvate lyase. Here we show, by cloning and characterizing an Arabidopsis defence-related gene (SID2) defined by mutation, that SA is synthesized from chorismate by means of ICS, and that SA made by this pathway is required for LAR and SAR responses.
2,089 citations
TL;DR: Recent advances made in understanding the role of salicylic acid, jasmonates and ethylene in modulating plant defence responses against various diseases and pests are reviewed.
Abstract: Plant hormones play important roles in regulating developmental processes and signaling networks involved in plant responses to a wide range of biotic and abiotic stresses. Significant progress has been made in identifying the key components and understanding the role of salicylic acid (SA), jasmonates (JA) and ethylene (ET) in plant responses to biotic stresses. Recent studies indicate that other hormones such as abscisic acid (ABA), auxin, gibberellic acid (GA), cytokinin (CK), brassinosteroids (BR) and peptide hormones are also implicated in plant defence signaling pathways but their role in plant defence is less well studied. Here, we review recent advances made in understanding the role of these hormones in modulating plant defence responses against various diseases and pests.
2,072 citations
TL;DR: The accumulation of red or purple flavonoids is a hallmark of plant stress and mounting evidence points to diverse physiological functions for these compounds in the stress response.
1,654 citations
TL;DR: The environmental induction of anthocyanins and their proposed importance in ameliorating environmental stresses induced by visible and UVB radiation, drought and cold temperatures are reviewed.
Abstract: — Anthocyanins are water-soluble pigments found in all plant tissues throughout the plant kingdom. Our understanding of anthocyanin biosynthesis and its molecular control has greatly improved in the last decade. The adaptive advantages of anthocyanins, especially in non-reproductive tissues, is much less clear. Anthocyanins often appear transiently at specific developmental stages and may be induced by a number of environmental factors including visible and UVB radiation, cold temperatures and water stress. The subsequent production and localization of anthocyanins in root, stem and especially leaf tissues may allow the plant to develop resistance to a number of environmental stresses. This article reviews the environmental induction of anthocyanins and their proposed importance in ameliorating environmental stresses induced by visible and UVB radiation, drought and cold temperatures.
1,425 citations