Genomics and Transcriptomics Analysis of Metal Accumulator Plants in Brassicaceae

Genomics and Transcriptomics Analysis of Metal Accumulator Plants in Brassicaceae

Abdul , Razaque Memon

some of the economically high valuable vegetables and oilseed crops used worldwide. The major industrial and food crops in Brassica are the closest relatives to the model plant Arabidopsis thaliana, and hence are major beneficiaries from the vast data of genomics and molecular genetics available in the database of Arabidopsis thaliana. Extensive genetic and molecular analyses have been undertaken for the six cultivated Brassica species. The four closely related crop species B. rapa (AA, 2n=20), B. juncea (AABB, 2n=36), B. napus (AACC, 2n=38), and B. carinata (BBCC, 2n=34) provide about 12% of the worldwide edible oil supply. The other two species B. nigra (BB, 2n=16) and B. oleracea (CC, 2n=18) provide many vegetables for healthy human diet having a valuable source of dietary fiber, vitamin C and other anticancer compounds. The comparative mapping between Arabidopsis thaliana and the well known oil crops in Brassicaceae, coupled with the basic knowledge of mutation based functional analysis in Arabidopsis thaliana and QTL mapping in Brassicas, could greatly contribute towards a better understanding of the genetic architecture for the conserved as well as the evolved traits of agronomic value of crop plants in Brassicaceae. Brassica nigra has the second smallest genome size (~ 632 Mbp) among the six cultivated species of Brassica. Approximately 25% of the documented metal hyper accumulating species are members of the Brassicaceae and some of them are being used for phytoremediation. The super metal accumulating capacity of Arabidopsis halleri and Thlaspi caerulescens have been well documented. Because of their slow growth and low biomass, other fast-growing and high biomass brassica crop plants, for example Brassica juncea and Brassica nigra have been evaluated for their ability to hyper accumulate metals from contaminated soils. The Diyabeker ecotype of B. nigra collected from southeastern part of Turkey was found to be hyperaccumulator of Cu. We carried out the comparative transcriptome analysis in order to find out the expression level of metal induced genes and transcriptome changes both in low and high Cu treated plants. Microarray analysis showed that some of the genes were highly expressed (several hundred fold) with Cu treated plants compared to control. Our microarray data using Affymetrix GeneChip Arabidopsis Genome Array (ATH1-121501 Genechip) indicate that possibly several genes including the genes in glutathione pathway, metal ATPase and ABC transporters are involved in metal tolerances in this ecotype.

Conference or Workshop Item
PeerReviewed

2012-05-31

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