Mitochondrial gene expression analysis reveals aberrant transcription of cox3 in Gossypium barbadense CMS line H276A.

Cotton cytoplasmic male sterility (CMS) has been extensively studied; however, information regarding its molecular mechanisms has not yet been disclosed. Therefore, to explore the molecular mechanism of pollen abortion of cotton CMS line H276A, transcript profiles of 30 mitochondrial protein-encoding genes at tetrad stage were conducted with northern blot and a differential expression gene cox3 was identified. Quantitative reverse-transcribed PCR (qRT-PCR) analysis indicated that the expression level of cox3 in the CMS line H276A was 0.39-fold compared to its maintainer line H276B. In addition, the immunoblot analysis revealed that the amount of COX3 protein was decreased to 59.38% in CMS line H276A. The 5` and 3` terminals of the transcript of cox3 in two materials were determined simultaneously with circularized RNA reverse-transcribed PCR (CR-RT-PCR). The data indicated that seven 5` end of transcript of cox3 in H276A (-451/-464/-465/-467/-471/-472/-508 respect to ATG) were identified which were different from that of H276B (-411/-412). A total of 15 single nucleotide polymorphisms (SNPs) was detected by clone sequencing analysis of upstream of cox3. To our knowledge, we are the first to comprehensively analyze the transcripts of the mitochondrial genome in the cotton CMS line and to identify the 5` and 3` terminals of the transcript of cox3 in cotton. Our data will provide a framework for a better understanding of molecular mechanisms of CMS and mitochondrial gene expression in cotton.

Characterization of functional genes GS3 and GW2 and their effect on the grain size of various landraces of rice (Oryza sativa).

BACKGROUND: Grain size is an essential factor of grain quality and yield in rice. The genetic studies have substantially contributed to enhancing yield and maintaining a good quality of rice. The two major genes GS3 (a negative regulator of grain length) and GW2 (a negative regulator of grain width) with functional mutation play a significant role in controlling the grain size of rice. METHODS AND RESULTS: In the study, 17 different widely grown Pakistani landraces of various genetic and geographic backgrounds were evaluated for grain phenotypic traits (1000-grain weight, length, width, and thickness) and also screened for genotypic mutation in GS3 and GW2 genes. Phenotypic data revealed the range for grain weight from 16.86 g (Lateefy) to 26.91 g (PS2), grain length ranged from 7.27 mm (JP-5) to 12.18 mm (PS2), grain width ranged from 2.01 mm (Lateefy) to 3.51 mm (JP5), and grain thickness ranged from 1.79 mm to 2.19. Correlation revealed a negative and significant correlation between grain width and length. There was no significant correlation between grain length and 1000-grain weight and grain width. LSD test displayed that the means of three variables grain length, grain width, and 1000-grain weight were statistically different from one another except grain width and grain breadth. Fifteen accessions carried the domesticated allele of GS3 while JP5 and Fakhr-e-Malakand carried the dominant allele. Similarly, fifteen accessions carried the dominant allele of GW2 while JP-5 and Fakhr-e-Malakand carried the mutant allele. CONCLUSIONS: The study shows that the mutant alleles of both genes are of significance to pyramid them in any breeding program. However, just incorporating favorable alleles is not the sole solution for improving the grain size. Therefore, further elucidation of GS3 and GW2 genes regulatory network, their interaction, trade-off, and pathways will better coordinate their marker-assisted selection in the future breeding program. Additionally, the study concluded that the selection of grain size was not dependent on 1000-grain weight in the selected germplasm.

The essence of NAC gene family to the cultivation of drought-resistant soybean (Glycine max L. Merr.) cultivars.

BACKGROUND: The NAC gene family is notable due to its large size, as well as its relevance in crop cultivation - particularly in terms of enhancing stress tolerance of plants. These plant-specific proteins contain NAC domain(s) that are named after Petunia NAM and Arabidopsis ATAF1/2 and CUC2 transcription factors based on the consensus sequence they have. Despite the knowledge available regarding NAC protein function, an extensive study on the possible use of GmNACs in developing soybean cultivars with superior drought tolerance is yet to be done. RESULTS: In response to this, our study was carried out, mainly through means of phylogenetic analysis (rice and Arabidopsis NAC genes served as seeding sequences). Through this, 139 GmNAC genes were identified and later grouped into 17 clusters. Furthermore, real-time quantitative PCR was carried out on drought-stressed and unstressed leaf tissues of both sensitive (B217 and H228) and tolerant (Jindou 74 and 78) cultivars. This was done to analyze the gene expression of 28 dehydration-responsive GmNAC genes. Upon completing the analysis, it was found that GmNAC gene expression is actually dependent on genotype. Eight of the 28 selected genes (GmNAC004, GmNAC021, GmNAC065, GmNAC066, GmNAC073, GmNAC082, GmNAC083 and GmNAC087) were discovered to have high expression levels in the drought-resistant soybean varieties tested. This holds true for both extreme and standard drought conditions. Alternatively, the drought-sensitive cultivars exhibited lower GmNAC expression levels in comparison to their tolerant counterparts. CONCLUSION: The study allowed for the identification of eight GmNAC genes that could be focused upon in future attempts to develop superior soybean varieties, particularly in terms of drought resistance. This study revealed that there were more dehydration-responsive GmNAC genes as (GmNAC004, GmNAC005, GmNAC020 and GmNAC021) in addition to what were reported in earlier inquiries. It is important to note though, that discovering such notable genes is not the only goal of the study. It managed to put emphasis on the significance of further understanding the potential of soybean GmNAC genes, for the purpose of enhancing tolerance towards abiotic stress in general. This scientific inquiry has also revealed that cultivar genotypes tend to differ in their drought-induced gene expression.

Foliar application of gibberellic acid endorsed phytoextraction of copper and alleviates oxidative stress in jute (Corchorus capsularis L.) plant grown in highly copper-contaminated soil of China.

Copper (Cu) is an abundant essential micronutrient element in various rocks and minerals and is required for a variety of metabolic processes in both prokaryotes and eukaryotes. However, excess Cu can disturb normal development by adversely affecting biochemical reactions and physiological processes in plants. The present study was conducted to explore the potential of gibberellic acid (GA3) on fibrous jute (Corchorus capsularis L.) seedlings grown on Cu mining soil obtained from Hubei Province China. Exogenous application of GA3 (10, 50, and 100 mg/L) on 60-day-old seedlings of C. capsularis which was able to grow in highly Cu-contaminated soil (2221 mg/kg) to study different morphological, physiological, and Cu uptake and accumulation in different parts of C. capsularis seedlings. According to the results, increasing concentration of GA3 (more likely 100 mg/L) alleviates Cu toxicity in C. capsularis seedlings by increasing plant growth, biomass, photosynthetic pigments, and gaseous exchange attributes. The results also showed that exogenous application of GA3 reduced oxidative stress in C. capsularis seedlings by the generation of extra reactive oxygen species (ROS). The reduction in oxidative stress in C. capsularis seedlings is because that plant has strong enzymatic antioxidants [superoxidase dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT)], which ultimately increased their activities to overcome oxidative damage in the cells/tissues. In addition to the plant growth, biomass, and photosynthesis, foliar application of GA3 also helps to increase metal (Cu) concentration in different parts of the plants when compared to 0 mg/L of application of GA3. From these findings, we can conclude that foliar application of GA3 plays a promising role in reducing ROS generation in the plant cells/tissues and increased phytoextraction of Cu in different plant parts. However, more investigation is needed on field experiments to find a combination of GA3 with a very higher concentration of Cu using fibrous C. capsularis.

De novo transcriptome sequencing and metabolite profiling analyses reveal the complex metabolic genes involved in the terpenoid biosynthesis in Blue Anise Sage (Salvia guaranitica L.).

Many terpenoid compounds have been extracted from different tissues of Salvia guaranitica. However, the molecular genetic basis of terpene biosynthesis pathways is virtually unknown. In this study, approximately 4 Gb of raw data were generated from the transcriptome of S. guaranitica leaves using Illumina HiSeq 2000 sequencing. After filtering and removing the adapter sequences from the raw data, the number of reads reached 32 million, comprising 186 million of high-quality nucleotide bases. A total of 61,400 unigenes were assembled de novo and annotated for establishing a valid database for studying terpenoid biosynthesis. We identified 267 unigenes that are putatively involved in terpenoid metabolism (including, 198 mevalonate and methyl-erythritol phosphate (MEP) pathways, terpenoid backbone biosynthesis genes and 69 terpene synthases genes). Moreover, three terpene synthase genes were studied for their functions in terpenoid biosynthesis by using transgenic Arabidopsis; most transgenic Arabidopsis plants expressing these terpene synthetic genes produced increased amounts of terpenoids compared with wild-type control. The combined data analyses from the transcriptome and metabolome provide new insights into our understanding of the complex metabolic genes in terpenoid-rich blue anise sage, and our study paves the way for the future metabolic engineering of the biosynthesis of useful terpene compounds in S. guaranitica.