Does epigenetic polymorphism contribute to phenotypic variances in Jatropha curcas L.?

Abstract

BackgroundThere is a growing interest in Jatropha curcas L. (jatropha) as a biodiesel feedstock plant. Variations in its morphology and seed productivity have been well documented. However, there is the lack of systematic comparative evaluation of distinct collections under same climate and agronomic practices. With the several reports on low genetic diversity in jatropha collections, there is uncertainty on genetic contribution to jatropha morphology.ResultIn this study, five populations of jatropha plants collected from China (CN), Indonesia (MD), Suriname (SU), Tanzania (AF) and India (TN) were planted in one farm under the same agronomic practices. Their agronomic traits (branching pattern, height, diameter of canopy, time to first flowering, dormancy, accumulated seed yield and oil content) were observed and tracked for two years. Significant variations were found for all the agronomic traits studied. Genetic diversity and epigenetic diversity were evaluated using florescence Amplified Fragment Length Polymorphism (fAFLP) and methylation sensitive florescence AFLP (MfAFLP) methods. Very low level of genetic diversity was detected (polymorphic band <0.1%) within and among populations. In contrast, intermediate but significant epigenetic diversity was detected (25.3% of bands were polymorphic) within and among populations. More than half of CCGG sites surveyed by MfAFLP were methylated with significant difference in inner cytosine and double cytosine methylation among populations. Principal coordinates analysis (PCoA) based on Nei's epigenetic distance showed Tanzania/India group distinct from China/Indonesia/Suriname group. Inheritance of epigenetic markers was assessed in one F1 hybrid population between two morphologically distinct parent plants and one selfed population. 30 out of 39 polymorphic markers (77%) were found heritable and followed Mendelian segregation. One epiallele was further confirmed by bisulphite sequencing of its corresponding genomic region.ConclusionOur study confirmed climate and practice independent differences in agronomic performance among jatropha collections. Such agronomic trait variations, however, were matched by very low genetic diversity and medium level but significant epigenetic diversity. Significant difference in inner cytosine and double cytosine methylation at CCGG sites was also found among populations. Most epigenetic differential markers can be inherited as epialleles following Mendelian segregation. These results suggest possible involvement of epigenetics in jatropha development.

Development of marker-free transgenic Jatrophaplants with increased levels of seed oleic acid

“…Four T0 trees with high oleic acid trait (oleic acid content > 70% of total fatty acid in T1 seed, including X8#34 and X8#291), 16 T0 transgenic trees with non-high oleic acid and two control wild-type Jc -MD plants were monitored for the following agronomic traits: plant height, number of primary branches after one trimming, diameter of main stem, seed number per fruit and seed number per tree after transplanting (September 2009 to June 2011). Previous studies have shown that Jc -MD was the earliest to flower and the most productive cultivar in field trials [17]. Under our greenhouse conditions, it took almost one year to flower and there was an average of 12 seeds per tree with an average seed weight of 330 mg, which was comparable to T0 high oleic plants and T0 non-high oleic plants as shown in Table 1.…”

DNA methylation changes in triticale due to in vitro culture plant regeneration and consecutive reproduction

“…Contrary to marker-based approaches, high performance liquid chromatography (HPLC) has been applied in studies of DNA methylation of plants regenerated via tissue culture (Renau-Morata et al 2005;Rival et al 2013). This technique supports general information on global DNA methylation and could be applied for the evaluation of differences among plant materials that could be related to spontaneously arising off-type plants (Johannes et al 2009;Yi et al 2010).…”

A New Jatropha curcas Variety (JO S2) with Improved Seed Productivity

“…In a similar study on 72 J. curcas accessions representing 13 countries, biochemical composition analysis of seeds showed wide variation in seed kernel crude protein, oil content, ash content and phorbol ester (PE) in seed [12]. Similarly, a two year progeny field trial conducted in Singapore with accessions from India, Indonesia, China, Africa and South America found significant variability in 1 year and 2 year accumulated seed yield, plant height at 2 year, number of primary branches, number of flowering branches, dormancy during drought period, time from seed sowing to first flowering as well as seed oil content [13]. For commercial plantation, there is the urgent need for improvement towards higher seed productivity and better uniformity in field.…”