Dataset Information

A genomewide analysis of the cinnamyl alcohol dehydrogenase family in sorghum [Sorghum bicolor (L.) Moench] identifies SbCAD2 as the brown midrib6 gene.

ABSTRACT: The content and composition of the plant cell wall polymer lignin affect plant fitness, carbon sequestration potential, and agro-industrial processing. These characteristics, are heavily influenced by the supply of hydroxycinnamyl alcohol precursors synthesized by the enzyme cinnamyl alcohol dehydrogenase (CAD). In angiosperms, CAD is encoded by a multigene family consisting of members thought to have distinct roles in different stages of plant development. Due to the high sequence similarity among CAD genes, it has been challenging to identify and study the role of the individual genes without a genome sequence. Analysis of the recently released sorghum genome revealed the existence of 14 CAD-like genes at seven genomic locations. Comparisons with maize and rice revealed subtle differences in gene number, arrangement, and expression patterns. Sorghum CAD2 is the predominant CAD involved in lignification based on the phylogenetic relationship with CADs from other species and genetic evidence showing that a set of three allelic brown midrib (bmr) lignin mutants contained mutations in this gene. The impact of the mutations on the structure of the protein was assessed using molecular modeling based on X-ray crystallography data of the closely related Arabidopsis CAD5. The modeling revealed unique changes in structure consistent with the observed phenotypes of the mutants.

SUBMITTER: Saballos A

PROVIDER: S-EPMC2644965 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature

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A genomewide analysis of the cinnamyl alcohol dehydrogenase family in sorghum [Sorghum bicolor (L.) Moench] identifies SbCAD2 as the brown midrib6 gene.

Saballos Ana A Ejeta Gebisa G Sanchez Emiliano E Kang Chulhee C Vermerris Wilfred W

Genetics 20081215 2

The content and composition of the plant cell wall polymer lignin affect plant fitness, carbon sequestration potential, and agro-industrial processing. These characteristics, are heavily influenced by the supply of hydroxycinnamyl alcohol precursors synthesized by the enzyme cinnamyl alcohol dehydrogenase (CAD). In angiosperms, CAD is encoded by a multigene family consisting of members thought to have distinct roles in different stages of plant development. Due to the high sequence similarity am ...[more]

PMID: 19087955

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Project description:WRKY transcription factors regulate diverse biological processes in plants, including abiotic and biotic stress responses, and constitute one of the largest transcription factor families in higher plants. Although the past decade has seen significant progress towards identifying and functionally characterizing WRKY genes in diverse species, little is known about the WRKY family in sorghum (Sorghum bicolor (L.) moench). Here we report the comprehensive identification of 94 putative WRKY transcription factors (SbWRKYs). The SbWRKYs were divided into three groups (I, II, and III), with those in group II further classified into five subgroups (IIa-IIe), based on their conserved domains and zinc finger motif types. WRKYs from the model plant Arabidopsis (Arabidopsis thaliana) were used for the phylogenetic analysis of all SbWRKY genes. Motif analysis showed that all SbWRKYs contained either one or two WRKY domains and that SbWRKYs within the same group had similar motif compositions. SbWRKY genes were located on all 10 sorghum chromosomes, and some gene clusters and two tandem duplications were detected. SbWRKY gene structure analysis showed that they contained 0-7 introns, with most SbWRKY genes consisting of two introns and three exons. Gene ontology (GO) annotation functionally categorized SbWRKYs under cellular components, molecular functions and biological processes. A cis-element analysis showed that all SbWRKYs contain at least one stress response-related cis-element. We exploited publicly available microarray datasets to analyze the expression profiles of 78 SbWRKY genes at different growth stages and in different tissues. The induction of SbWRKYs by different abiotic stresses hinted at their potential involvement in stress responses. qRT-PCR analysis revealed different expression patterns for SbWRKYs during drought stress. Functionally characterized WRKY genes in Arabidopsis and other species will provide clues for the functional characterization of putative orthologs in sorghum. Thus, the present study delivers a solid foundation for future functional studies of SbWRKY genes and their roles in the response to critical stresses such as drought.

Project description:BackgroundAcyl carrier proteins (ACP) constitute a very conserved carrier protein family. Previous studies have found that ACP not only takes part in the fatty acid synthesis process of almost all organisms, but also participates in the regulation of plant growth, development, and metabolism, and makes plants adaptable to stresses. However, this gene family has not been systematically studied in sorghum.ResultsNine ACP family members were identified in the sorghum genome, which were located on chromosomes 1, 2, 5, 7, 8 and 9, respectively. Evolutionary analysis among different species divided the ACP family into four subfamilies, showing that the SbACPs were more closely related to maize. The prediction results of subcellular localization showed that SbACPs were mainly distributed in chloroplasts and mitochondria, while fluorescence localization showed that SbACPs were mainly localized in chloroplasts in tobacco leaf. The analysis of gene structure revealed a relatively simple genetic structure, that there were 1-3 introns in the sorghum ACP family, and the gene structure within the same subfamily had high similarity. The amplification method of SbACPs was mainly large fragment replication, and SbACPs were more closely related to ACPs in maize and rice. In addition, three-dimensional structure analysis showed that all ACP genes in sorghum contained four α helices, and the second helix structure was more conserved, implying a key role in function. Cis-acting element analysis indicated that the SbACPs might be involved in light response, plant growth and development regulation, biotic and abiotic stress response, plant hormone regulation, and other physiological processes. What's more, qRT-PCR analysis uncovered that some of SbACPs might be involved in the adaptive regulation of drought and salt stresses, indicating the close relationship between fatty acids and the resistance to abiotic stresses in sorghum.ConclusionsIn summary, these results showed a comprehensive overview of the SbACPs and provided a theoretical basis for further studies on the biological functions of SbACPs in sorghum growth, development and abiotic stress responses.

Project description:Cinnamyl alcohol dehydrogenase (CAD) is involved in the final step of the phenylpropanod pathway, catalyzing the NADPH-dependent reduction of hydroxy-cinnamaldehydes into the corresponding alcohols. The rice genome contains twelve CAD and CAD-like genes, collectively called OsCADs. To elucidate the biochemical function of the OsCADs, OsCAD1, 2, 6, and 7, which are highly expressed in rice, were cloned from rice tissues. The cloned OsCADs were heterologously expressed in Escherichia coli as His-tag fusion proteins. The activity assay of the recombinant OsCADs showed that OsCAD2, 6, and 7 have CAD activity toward hydroxycinnamaldehydes, but OsCAD1 has no detectable catalytic activity. The kinetic parameters of the enzyme reactions demonstrated that OsCAD2 has the highest catalytic activity among the examined enzymes. This result agrees well with the finding that the Zn binding and NADPH binding motifs and the residues constituting the substrate binding pocket in bona fide plant CADs were fully conserved in OsCAD2. Although they have large variations in the residue for the substrate binding pocket, OsCAD6 and 7 catalyzed the reduction of hydroxycinnamaldehydes with a similar efficiency. Alignment of amino acid sequences showed that OsCAD1 lacks the GxxxxP motif for NADPH binding and has mismatches in residues important in the reduction process, which could be responsible for the loss of catalytic activity. OsCAD2 belongs to CAD Class I with bona fide CADs from other plant species and is constitutively expressed throughout the developmental stages of rice, with preferential expression in actively lignifying tissues such as the root, stem, and panicle, suggesting that it is mainly involved in developmental lignification in rice. The expression of OsCAD2 was also induced by biotic and abiotic stresses such as Xanthomonas oryzae pv. oryzae (Xoo) infection and UV-irradiation, suggesting that it plays a role in the defense response of rice, in addition to a bona fide role in developmental lignification. OsCAD6 and 7 belong in CAD Class II. Their expression is relatively lower than that of OsCAD2 and is confined to certain tissues, such as the leaf sheath, stem, and panicle. The expression of OsCAD6 was stimulated by Xoo infection and UV-irradiation. Thus OsCAD6 appears to be an inducible OsCAD that is likely involved in the defense response of rice against biotic and abiotic stresses.

Project description:Sorghum production is affected by a wide array of biotic constraints, of which sorghum shoot fly, Atherigona soccata is the most important pest, which severely damages the sorghum crop during the seedling stage. Host plant resistance is one of the major components to control sorghum shoot fly, A. soccata. To understand the nature of gene action for inheritance of shoot fly resistance, we evaluated 10 parents, 45 F1's and their reciprocals in replicated trials during the rainy and postrainy seasons. The genotypes ICSV 700, Phule Anuradha, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited resistance to shoot fly damage across seasons. Crosses between susceptible parents were preferred for egg laying by the shoot fly females, resulting in a susceptible reaction. ICSV 700, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited significant and negative general combining ability (gca) effects for oviposition, deadheart incidence, and overall resistance score. The plant morphological traits associated with expression of resistance/susceptibility to shoot fly damage such as leaf glossiness, plant vigor, and leafsheath pigmentation also showed significant gca effects by these genotypes, suggesting the potential for use as a selection criterion to breed for resistance to shoot fly, A. soccata. ICSV 700, Phule Anuradha, IS 2146 and IS 18551 with significant positive gca effects for trichome density can also be utilized in improving sorghums for shoot fly resistance. The parents involved in hybrids with negative specific combining ability (sca) effects for shoot fly resistance traits can be used in developing sorghum hybrids with adaptation to postrainy season. The significant reciprocal effects of combining abilities for oviposition, leaf glossy score and trichome density suggested the influence of cytoplasmic factors in inheritance of shoot fly resistance. Higher values of variance due to specific combining ability (σ(2)s), dominance variance (σ(2)d), and lower predictability ratios than the variance due to general combining ability (σ(2)g) and additive variance (σ(2)a) for shoot fly resistance traits indicated the predominance of dominance type of gene action, whereas trichome density, leaf glossy score, and plant vigor score with high σ(2)g, additive variance, predictability ratio, and the ratio of general combining ability to the specific combining ability showed predominance of additive type of gene action indicating importance of heterosis breeding followed by simple selection in breeding shoot fly-resistant sorghums. Most of the traits exhibited high broadsense heritability, indicating high inheritance of shoot fly resistance traits.

Dataset Information

A genomewide analysis of the cinnamyl alcohol dehydrogenase family in sorghum [Sorghum bicolor (L.) Moench] identifies SbCAD2 as the brown midrib6 gene.

Publications

A genomewide analysis of the cinnamyl alcohol dehydrogenase family in sorghum [Sorghum bicolor (L.) Moench] identifies SbCAD2 as the brown midrib6 gene.

Similar Datasets

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