PhD student (3rd Year), University of Nottingham Malaysia Campus - Crops For the Future (CFF)


Genetic dissection of winged bean development and plant architecture related traits

Winged bean (Psophocarpus tetragonolobus) is a legume crop that could contribute to food security in hot and humid areas in Asia and the Pacific. Once called "the soybean of the tropics", it received considerable attention during 70s and 80s, but only recent advances in technology can boost the investigation into how this crop species develops and grow.

My research started with controlled crosses (breeding) between parents that differ in plant structure (e.g. their number of branches, number of internodes) and in development (how long they take to flower? how fast they can grow?). The analysis of the derived F2 population (the second generation originated from the initial crosses) shows how plant structure and development related traits/characteristics are controlled at genetic level (how many genes are involved? how are they inherited?). The final aim is then to generate the first linkage map for winged bean, where it'll be possible to begin to see which regions of the genome control the analysed traits. The final impact of this research is to provide the first bases to improve winged bean, for enhance its productivity and help sustaining food security in Asia and the Pacific region.

Noteworthy, we have also developed and published the first ever set of validated SSR markers in winged bean: DOI 10.3390/genes8030100. Suck markers are like "flags", each representing one region of the DNA of an organism. With these we have been able to see which winged bean individuals from different geographical areas were more, or less related to each others at genomic level.


Development of high-lysine rice via endosperm-specific expression of a foreign LYSINE RICH PROTEIN gene.

Abstract: Lysine (Lys) is considered to be the first limiting essential amino acid in rice. Although there have been extensive efforts to improve the Lys content of rice through traditional breeding and genetic engineering, no satisfactory products have been achieved to date.We expressed a LYSINE-RICH PROTEIN gene (LRP) from Psophocarpus tetragonolobus (L.) DC using an endosperm-specific GLUTELIN1 promoter (GT1) in Peiai64S (PA64S), an elite photoperiod-thermo sensitive male sterility (PTSMS) line. The expression of the foreign LRP protein was confirmed by Western blot analysis. The Lys level in the transgenic rice seeds increased more than 30 %, the total amount of other amino acids also increased compared to wild-type. Persistent investigation of amino acids in 3 generations showed that the Lys content was significantly increased in seeds of transgenic rice. Furthermore, Lys content in the hybrid of the transgenic plants also had an approximate 20 % increase compared to hybrid control. At the grain-filling stage, we monitored the transcript abundance of many genes encoding key enzymes involved in amino acid metabolism, and the results suggested that reduced amino acid catabolism led to the accumulation of amino acids in the transgenic plants. The genetically engineered rice showed unfavorable grain phenotypes compared to wild-type, however, its hybrid displayed little negative effects on grain.Endosperm-specific expression of foreign LRP significantly increased the Lys content in the seeds of transgenic plant, and the the Lys increase was stably heritable with 3 generation investigation. The hybrid of the transgenic plants also showed significant increases of Lys content in the seeds. These results indicated that expression of LRP in rice seeds may have promising applications in improving Lys levels in rice.

Pub.: 01 Jul '16, Pinned: 05 Oct '17

De novo sequencing and comparative analysis of leaf transcriptomes of diverse condensed tannin-containing lines of underutilized Psophocarpus tetragonolobus (L.) DC.

Abstract: Condensed tannin (CT) or proanthocyanidin (PA) is a unique group of phenolic metabolite with high molecular weight with specific structure. It is reported that, the presence of high-CT in the legumes adversely affect the nutrients in the plant and impairs the digestibility upon consumption by animals. Winged bean (Psophocarpus tetragonolobus (L.) DC.) is one of the promising underutilized legume with high protein and oil-content. One of the reasons for its underutilization is due to the presence of CT. Transcriptome sequencing of leaves of two diverse CT-containing lines of P. tetragonolobus was carried out on Illumina Nextseq 500 sequencer to identify the underlying genes and contigs responsible for CT-biosynthesis. RNA-Seq data generated 102586 and 88433 contigs for high (HCTW) and low CT (LCTW) lines of P. tetragonolobus, respectively. Based on the similarity searches against gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) database revealed 5210 contigs involved in 229 different pathways. A total of 1235 contigs were detected to differentially express between HCTW and LCTW lines. This study along with its findings will be helpful in providing information for functional and comparative genomic analysis of condensed tannin biosynthesis in this plant in specific and legumes in general.

Pub.: 23 Mar '17, Pinned: 05 Oct '17