Agri Gene最新文献

Modern breeding practice of small grain cereals necessitates the development of an efficient system for the large scale and reproducible production of the doubled haploid (DH) lines. It is believed that among the available DH generation techniques, only isolated microspore culture (IMC) can satisfy the demand of public and private breeding programs. Unfortunately, the IMC method is prone to several challenges that jeopardizes its large scale adoption. One of the approaches to limit the variation in DH plant production and increase the efficiency of the method is manipulation of embryogenesis-related genes. Here we set up a study to map BABY BOOM in a bread wheat genome. The gene is one of the morphogenic regulators of somatic embryogenesis in plants. To achieve this task, we used amino acid sequences of Zea mays BBM-like proteins. TaBBM homoeologs were mapped to chromosomes 6AL, 6BL and 6DL. Amino acid sequence analysis revealed the presence of two AP2 domains and bbm-1 motif in the A and D copies and only one AP2 domain and bbm-1 motif in the B copy. This, along with the absence of both gene expression and predictable TATA-box, suggests that TaBBM-gB is a pseudogene. The expression pattern of the identified A and D homoeologs was similar to that for the BBM-like genes in other species and presence of the transcript was detected in an embryogenic microspore population. Identification of the TaBBM homolog can have application in elevating the efficiency of DH production, tissue culture, plant transformation and genome editing for wheat improvement.

Plant alcohols and aldehydes are produced by the action of alcohol dehydrogenases (ADH) and play an important role during fruit ripening and aroma production. Alcohols are not only produced in different tissues at different stages of plant development but are also products of the fermentative pathway which gets activated by different stresses, including hypoxia. The ADH gene is a well-established marker for hypoxic response as well as plant aroma. In a previous report we have identified and characterized three ADHs (MiADH1, 2, 3) from Dashehari mango. MiADH1 was found to be fruit specific and was upregulated by ethylene and ABA, suggesting a role in fruit aroma volatile production. In order to functionally characterize MiADH1, transgenic tomato plants were developed under the control of the constitutive (CaMV35S) promoter. Transgenic tomato fruit expressing MiADH1 gene showed a change in the levels of several alcohols and aldehydes related to flavor in comparison to the control. The change in aroma and volatiles compounds was more prominent during the ripe stage as compared to unripe and mid-ripe stages of tomato fruit. The transgenic tomato plants also produced adventitious roots. Our results suggest that the overexpression of MiADH1 in tomato plants induced the fermentative pathway in roots, and mimicked hypoxic response by development of adventitious roots from the stem as an adaptive mechanism.

The objective of the current study was to evaluate transcript activity of motile-rich sperm collected from June (spring) or August (summer), stored as cooled-extended (ExT) or cryopreserved (FrZ), and selected for least or most sperm head shape change, using Fourier harmonic analysis techniques, between June and August. Even with the lack of an extended heat stress, motile-rich sperm transcripts were influenced by season and putatively by sperm head shape change. Transcripts that had previously been associated with seasonality of sperm collection and methylation pathway transcripts were evaluated among semen samples. Calcium-regulated heat-stable protein 1-like transcript from motile-rich sperm tended (P = 0.0829) to be greater in samples collected in June in comparison to August samples. Ferritin light polypeptide transcript tended (P = 0.0838) to be greater from motile-rich sperm with least head shape change from June collection in contrast to sperm collected in August. Both transcripts have a functional role in cytoprotection and may serve to improve boar semen activity and quality during thermal stress or seasonal changes.

Plants respond to stress conditions by altering genetic pathways. In this study, we aimed to identify and analyze differentially expressed genes in leaves of two grape varieties (genotypes) that were grown in Palestine either in a semi-arid region with a prolonged drought and high temperature stress or in a temperate region with moderate stress levels. In total, twelve transcripts with altered expression patterns, either by stress or genotype, were identified with the differential display RT-PCR (DDRT-PCR) technique and validated via quantitative real-time PCR (qRT-PCR). Eight transcripts represent genes that are down-regulated by stress in the leaves of at least one variety, among of which are members of the DEAD-box RNA helicase, Haloacid Dehalogenase (HAD) hydrolase, kinesin-like, and mitochondrial Adenine nucleotide transporter (ANT) gene families. Two genes encoding for members of the GDSL Lipase/Esterase and Multiprotein Bridging Factor (MBF) gene families were found to be up-regulated in stressed leaves. Two transcripts coding for a NAC-domain containing protein and a WD-repeat containing protein, respectively, were found to be non-responsive to those abiotic stresses but are differentially expressed in a genotype-dependent manner.

Lipid metabolism in fish which is a complex phenomenon has been studied in the past few years as its gradually gaining interest from researchers. Lipids serve essential roles in both physiological and life cycle of fish. In this study, we review the functions of some genes and enzymes that are related to the metabolism of lipids in fish. We also review how these enzymes and genes are affected by different lipid sources since alternative lipids are being sought for. From the study, genes such as PPARs, ACC, SCD, FASN, CPT, ACYL and a host of others regulate the lipid metabolic pathways.

Chitinases are thought to play a role in plant resistance to pathogens, but the extent of this role is unknown. The gene for a maize (Zea mays) chitinase, “chitinase 2”, previously reported to be induced by two ear rot pathogens in one maize inbred, was cloned from mRNA isolated from milk stage kernels of several different inbreds reported to be susceptible or resistant to ear rot pathogens. The chitinase gene sequence of some of the susceptible inbreds had frame shifts which would result in a nonfunctional protein. Other susceptible inbreds, and a few resistant inbreds, were missing regions that would contribute to chitin binding. A putative functional clone from a resistant inbred was expressed in yeast, and produced a protein with chitinase activity against different oligomers of N-acetyl glucosamine and modified chitin. The yeast-produced chitinase was also resistant to degradation by proteases from maize ear rot fungi, and enhanced antifungal activity of miconazole towards Fusarium graminearum. When introduced in maize callus transgenically, the callus expressing the chitinase 2 gene had significantly less growth of the ear rot pathogen, F. graminearium, than callus which did not express the gene. This information suggests susceptibility and resistance to ear rot pathogens is influenced not only by expression levels, but also by the sequence of putative resistance genes. Previous reports of increased expression of putative resistance genes need to be tempered with the realization that they may play no role in resistance if the genes code for nonfunctional or reduced function proteins.

Coconut palms are propagated mainly through nuts, which does not meet the requirement of quality planting materials for large scale planting. In vitro propagation to enhance production of high yielding, disease-free planting material in coconut has remained a distant reality because of its in vitro recalcitrance. MicroRNAs (miRNAs) have been implicated in the regulation of a plethora of cellular, physiological and developmental processes which include developmental regulation, hormone response and adaptation to stresses. In this study, computational methods were utilized to identify conserved miRNA from transcriptome data of coconut embryogenic calli. A total of 117,790 unigenes from coconut embryogenic calli were compared against monocot mature miRNA sequences. A total of 27 mature miRNA sequences, belonging to 15 miRNA families, viz. miR156, miR164, miR166, miR167, miR169, miR171, miR172, miR394, miR397, miR408, miR444, miR535, miR827, miR1134 and miR2118, were identified. Many of these have well defined and crucial roles in developmental pathways and hormone signalling in other plant species. Each of the identified miRNA had its own predicted targets. This is the first in silico study describing miRNAs and their role in the regulation of in vitro embryogenesis in coconut. The results obtained in this study would provide a base for future studies to address molecular mechanisms that govern in vitro recalcitrance in coconut and the role of miRNAs in the process.

Determining the genes responsible for pest resistance in maize can allow breeders to develop varieties with lower losses and less contamination with undesirable toxins. A gene sequence coding for a geranyl geranyl transferase-like protein located in a fungal ear rot resistance quantitative trait locus was cloned from an inbred with reported resistance to Fusarium proliferatum and Fusarium verticillioides ear rot. Transgenic expression of the gene in maize callus reduced colonization by these two Fusarium species and also Fusarium graminearum relative to a β-glucuronidase (GUS) transformant control. Some transformants were also more insect resistant. The more fungal resistant transformant lines produced higher levels of headspace ethanol which were significantly associated with antifungal activity, especially for F. verticillioides. Maize pyruvate decarboxylase appears to have a moiety capable of interacting with the geranyl geranyl transferase, suggesting ethanol production is enhanced due to more efficient transfer of pyruvate through the mitochondrial membrane. Other undetermined mechanisms may also be enhancing resistance of the transformants to the Fusarium fungus, however. This is the first report of the involvement of a geranyl geranyl transferase-like sequence in fungal resistance in plants, and represents a novel mechanism for producing higher yielding and better quality maize.

Transcription factors (TFs) are essential regulators during gene expression. To better understand TF genes in tomato (Solanum lycopersicum L.), a silico genomic analysis of TF prediction was performed through the tomato genome. A total of 2026 TF genes were identified in the tomato genome, and they account for approximately 5.83% of its estimated total number of genes. These genes can be also classified into 57 families. The largest family is famous for the MYB superfamily and comprises 220 MYB TF genes. Predicted TFs were distributed across all 12 chromosomes with different densities. Chromosome 01 possesses 241 TFs, accounting for the largest number of TFs. According to microarray and expressed sequence tag data, expression patterns of 298 TFs showed that many of these TFs play roles in growth, development, diverse biological processes and responses to various stresses of S. lycopersicum L. Eight TF genes were further analyzed by reverse transcription polymerase chain reaction analysis in different tissues (root, stem, leaf, flower, and fruit). To the best of our knowledge, this study is the first to report genome-wide analysis of tomato TF gene families. This study provides valuable information regarding classification and putative functions of TFs in Solanaceae.

In the present study, selected indica rice accessions (basmati, non-basmati fragrant, and non-fragrant) were screened for mutations in betaine aldehyde dehydrogenase 2 (badh2) gene to investigate the allelic differences using previously reported functional markers. This screening experiment revealed that non-basmati fragrant accession ‘Velchi’ does not harbour any reported mutation in coding region of badh2. While working with badh2-p-UTR marker we got deviating results. All the non-basmati fragrant and basmati types gave amplicon of 203 bp except Velchi, whereas all non-fragrant and ‘Velchi’ gave 456 and 461 bp amplicons respectively. The new allele has 253 bp deletion in the promoter region of fragrant indica rice accessions compared to non-fragrant rice. Further, the fragrant accession ‘Velchi’ has additional 5 bp duplication as compared to non-fragrant accessions. To distinguish Velchi from other non-fragrant indica accessions, a new marker (velbadh2-p-UTR) has been designed to identify this 5 bp difference, which could distinguish ‘Velchi’ from non-fragrant rice accessions and can be useful in breeding for development of fragrant rice varieties via marker-assisted selection. The 2AP biosynthesis related metabolites, gene expression and enzyme assay confirmed deletion in badh2 and expression of fragrance in Velchi.