Development of transgenic imazapyr-tolerant cowpea (Vigna unguiculata)

Abstract

Here we present the development of cowpea lines tolerant to a herbicide from imidazoline class (imazapyr). Plants presented tolerance to fourfold the commercial recommended dose for weed control. Cowpea is one of the most important and widely cultivated legumes in many parts of the world. Its cultivation is drastically affected by weeds, causing damages during growth and development of plants, competing for light, nutrients and water. Consequently, weed control is critical, especially using no-tillage farming systems. In tropical regions, no-till farming is much easier with the use of herbicides to control weeds. This study was conducted to evaluate the possibility of obtaining transgenic cowpea plants resistant to imidazolinone, which would facilitate weed control during the summer season. The biolistic process was used to insert a mutated acetohydroxyacid synthase coding gene (Atahas) which confers tolerance to imazapyr. The transgene integration was confirmed by Southern blot analysis. Out of ten lines tested for tolerance to 100 g ha(-1) imazapyr, eight presented some tolerance. One line (named 59) revealed high herbicide tolerance and developmental growth comparable to non-transgenic plants. This line was further tested for tolerance to higher herbicide concentrations and presented tolerance to 400 g ha(-1) imazapyr (fourfold the commercial recommended dose) with no visible symptoms. Line 59 will be the foundation for generating imidazolinone-tolerant cowpea varieties, which will facilitate cultivation of this crop in large areas.

Grain Legumes

“…However, high transformation efficiency rates (75-90 % frequency) have been achieved by means of A. rhizogenes-mediated root transformation (Estrada-Navarrete et al 2006). Recently, Aragão et al (2013) has carried out the molecular characterization of the first commercial transgenic common bean immune to BGMV. Molecular analyses showed that the transgenes were structurally stable for eight self-pollinated generations and after backcrosses with a non-transgenic commercial variety.…”

“…Critical features of this system include suitable explants from cotyledonary nodes or embryonic axes and a tissue-culture regime without auxins, but which includes a cytokinin at low levels during shoot initiation. There are now several reports showing experimental evidence for reproducible gene transfer to cowpea including genes for resistance to pod borer (Higgins et al 2012) and cowpea weevil (Solleti et al 2008) as well as for weed control (Citadin et al 2013) and a range of model genes to evaluate the technology (Citadin et al 2011).…”

RNAi‐based enhanced resistance to Cowpea severe mosaic virus and Cowpea aphid‐borne mosaic virus in transgenic cowpea

“…Ivo et al . () have already reported a transformation system based on the bombardment of apical meristematic tissues, and this system has been used for introducing agronomic traits into this important crop (Citadin et al ., ). The frequency of transformation obtained in this work (1·04%) was similar to that previously reported (Ivo et al ., ).…”

“…Viral diseases, particularly those caused by CPSMV and CABMV, are an important constraint to the production of cowpea in tropical areas, especially in Latin America and Africa (Singh et al, 2003;Citadin et al, 2013). In this study, a reproducible system was used to routinely achieve transgenic cowpea plants to express a chimerical gene comprising a fragment from the proteinase cofactor gene of CPSMV and a fragment of the coat protein gene of CABMV (DCSMVCABMV).…”

Functional genomics to study stress responses in crop legumes: progress and prospects

“…Acharjee et al 2010), cowpea (e.g. Citadin et al 2013), pigeonpea (e.g. Sharma et al 2006), peanut (e.g.…”