Growth, reproductive phenology and yield responses of a potential biofuel plant, Jatropha curcas grown under projected 2050 levels of elevated CO2.

Jatropha (Jatropha curcas) is a non-edible oil producing plant which is being advocated as an alternative biofuel energy resource. Its ability to grow in diverse soil conditions and minimal requirements of essential agronomical inputs compared with other oilseed crops makes it viable for cost-effective advanced biofuel production. We designed a study to investigate the effects of elevated carbon dioxide concentration ([CO(2)]) (550 ppm) on the growth, reproductive development, source-sink relationships, fruit and seed yield of J. curcas. We report, for the first time that elevated CO(2) significantly influences reproductive characteristics of Jatropha and improve its fruit and seed yields. Net photosynthetic rate of Jatropha was 50% higher in plants grown in elevated CO(2) compared with field and ambient CO(2) -grown plants. The study also revealed that elevated CO(2) atmosphere significantly increased female to male flower ratio, above ground biomass and carbon sequestration potential in Jatropha (24 kg carbon per tree) after 1 year. Our data demonstrate that J. curcas was able to sustain enhanced rate of photosynthesis in elevated CO(2) conditions as it had sufficient sink strength to balance the increased biomass yields. Our study also elucidates that the economically important traits including fruit and seed yield in elevated CO(2) conditions were significantly high in J. curcas that holds great promise as a potential biofuel tree species for the future high CO(2) world.

Molecular cloning and characterisation of metallothionein type 2a gene from Jatropha curcas L., a promising biofuel plant.

In the present study, we have cloned a gene encoding JcMT2a protein from Jatropha curcas L., a promising biofuel tree species. Full length sequence of JcMT2a gene was isolated using RACE PCR. Heterologous expression of JcMT2a in Escherichia coli and its purification has shown distinct bands corresponding to the GST and GST-fused JcMT2a protein. Significant tolerance was observed in E. coli cells expressing recombinant GST-JcMT2a for zinc, copper and cadmium metals compared to cells expressing GST alone. JcMT2a also restored Cu and Cd tolerance in the metal sensitive yeast mutants. Quantitative real time PCR showed a significant increase in JcMT2a transcripts with Cu and Cd in the leaf compared to root tissue. Our Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis clearly demonstrates that J. curcas L. could be a potential candidate for phytoremediation to clean heavy metals from the environment, in addition to its non-edible oil seed yields for biodiesel production.

De novo transcriptome analysis of an imminent biofuel crop, Camelina sativa L. using Illumina GAIIX sequencing platform and identification of SSR markers.

Camelina sativa L. is an emerging biofuel crop with potential applications in industry, medicine, cosmetics and human nutrition. The crop is unexploited owing to very limited availability of transcriptome and genomic data. In order to analyse the various metabolic pathways, we performed de novo assembly of the transcriptome on Illumina GAIIX platform with paired end sequencing for obtaining short reads. The sequencing output generated a FastQ file size of 2.97 GB with 10.83 million reads having a maximum read length of 101 nucleotides. The number of contigs generated was 53,854 with maximum and minimum lengths of 10,086 and 200 nucleotides respectively. These trancripts were annotated using BLAST search against the Aracyc, Swiss-Prot, TrEMBL, gene ontology and clusters of orthologous groups (KOG) databases. The genes involved in lipid metabolism were studied and the transcription factors were identified. Sequence similarity studies of Camelina with the other related organisms indicated the close relatedness of Camelina with Arabidopsis. In addition, bioinformatics analysis revealed the presence of a total of 19,379 simple sequence repeats. This is the first report on Camelina sativa L., where the transcriptome of the entire plant, including seedlings, seed, root, leaves and stem was done. Our data established an excellent resource for gene discovery and provide useful information for functional and comparative genomic studies in this promising biofuel crop.

Paclobutrazol treatment as a potential strategy for higher seed and oil yield in field-grown Camelina sativa L. Crantz.

BACKGROUND: Camelina (Camelina sativa L. Crantz) is a non-food oilseed crop which holds promise as an alternative biofuel energy resource. Its ability to grow in a variety of climatic and soil conditions and minimal requirements of agronomical inputs than other oilseed crops makes it economically viable for advanced biofuel production. We designed a study to investigate the effect of paclobutrazol [2RS, 3RS)-1-(4-Chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol] (PBZ), a popular plant growth regulator, on the seed and oil yield of Camelina sativa (cv. Celine). RESULTS: A field-based micro-trial setup was established in a randomized block design and the study was performed twice within a span of five months (October 2010 to February 2011) and five different PBZ treatments (Control: T0; 25 mg l-1: T1; 50 mg l-1: T2; 75 mg l-1: T3; 100 mg l-1: T4; 125 mg l-1: T5) were applied (soil application) at the time of initiation of flowering. PBZ at 100 mg l-1 concentration (T4) resulted in highest seed and oil yield by 80% and 15%, respectively. The seed yield increment was mainly due to enhanced number of siliques per plant when compared to control. The PBZ - treated plants displayed better photosynthetic leaf gas exchange characteristics, higher chlorophyll contents and possessed dark green leaves which were photosynthetically active for a longer period and facilitated higher photoassimilation. CONCLUSION: We report for the first time that application of optimized PBZ dose can be a potential strategy to achieve higher seed and oil yield from Camelina sativa that holds great promise as a biofuel crop in future.