Characterization and functional validation of two scaffold attachment regions (SARs) from Cicer arietinum (L.)

A library of SARs has been prepared from chickpea by Illumina sequencing of DNA fragments that co-isolate with the nuclear scaffold by lithium diiodosalicylate treatment. Seven fragments were screened on the basis of SAR associated motifs and their interactions were tested with the nuclear scaffold of chickpea by in vitro binding assay. SAR 1 and SAR 2 bind strongly in comparison to other SARs to the nuclear scaffold of chickpea and tomato during in vitro binding assay. To investigate the effect of SARs on transgene expression and variation among transformants, NBRI 1.1 (harbouring GUS expression cassette with single SAR1 fragment), NBRI 2.1 (with single SAR2 fragment) and NBRI 1.2 (with two SAR1 fragments) vectors were prepared for plant transformation and transgenic tomato plants were developed, plants transformed with pBI121 functioned as a control. The enzymatic activity of GUS increased 9.52 fold in NBRI 2.1, 17.82 fold in NBRI 1.1 and 51.4 fold increase in NBRI 1.2 in comparison to pBI121. Chickpea was transformed with NBRI 1.2 and pBI121, where GUS enzymatic activity increased 13.789 fold in NBRI 1.2 in comparison to pBI121.