Cisgenesis and Intragenesis: Twin sisters for Crop Improvement

 

 

 One of the major concerns of the general public about transgenic crops relates to the mixing of genetic materials between species that cannot hybridize by natural means. To meet this concern, the two transformation concepts cisgenesis and intragenesis were developed as alternatives to transgenesis. Both concepts imply that plants must only be transformed with genetic material derived from the species itself or from closely related species capable of sexual hybridization. Furthermore, foreign sequences such as selection of genes and vector-backbone sequences should be absent².

           

In cisgenesis, the unchanged, contiguous and naturally occurring genome fragment containing the gene of interest along with its own introns and regulatory sequences are fragmented as such, and transferred into the host genome. Whereas in case of intragenesis, gene of interest is taken from other source while the regulatory elements and introns from another source and a new combination of DNA fragments are created artificially through in vitro rearrangement, but source should belong to the same species or from a cross compatible species. The gene used in cisgenic and intragenic approach is similar compared with classical breeding and also it overcomes the linkage dag¹.

 

            Cisgenesis is a promising approach that introduces native genes from the crops own gene pool using GM technology, thereby retaining favorable characteristics of established varieties. Jo et al. (2014) pursued a cisgenesis approach to introduce two broad spectrum potato late blight R genes, Rpi-sto1 and Rpi-vnt1.1 from the crossable species Solanum stoloniferum and Solanum venturii, respectively for potentially durable late blight resistant potatoes. Also in apple introduce the HcrVf2 gene in order to obtain polygenic durable resistance to apple scab (Venturia inaequalis).

 

Recently, intragenesis is applied to potato to get higher level amylopectin content. Moreover, the MdMYB10 transcription factor from apple that upregulates the anthocyanin pathway, leading to red-fleshed apples have also been introduced. Another cisgenic approach has been used in poplar in which plants with different growth types are produced due to overexpression of growth-related poplar genes. Till now, cisgenesis is still in research phase but in the coming 10 years, it will find its application in crop improvement¹.

 

References

 

1. DEVI, E. L., CHONGTHAM, S.K., HOLEYACHI, P., KOUSAR, N., SINGH, M., BEHERA, C., TELEM, R. S., SINGH, N. B. AND SHABIR, H. W., 2013, Cisgenesis and Intragenesis: Twin Sisters for Crop Improvement. Res. J. Agril. and Foret. Sci., 1(10): 22-26.

 

2. HOLME, I. B., WENDT, T. AND HOLM, P. B., 2013, Intragenesis and Cisgenesis as Alternatives to Transgenic Crop Development. Pl. Biotechnol. J., 11: 395-407.

 

3. JO, K., KIM, C., KIM, S., KIM, T., BERGERVOET, M., JONGSMA, M. A., VISSER, R., JACOBSEN, E. AND  VOSSEN, J.H., 2014, Development of Late blight Resistant Potatoes by Cisgene Stacking. BMC Biotechnol., 14: 50-60.