Transgenic approaches for genetic improvement in groundnut (Arachis hypogaea L.) against major biotic and abiotic stress factors

Abstract

Cultivated groundnut ( Arachis hypogaea L.) is considered as one of the primary oilseed crops and a major fodder for cattle industry in most of the developing countries, owing to its rich source of protein. It is due to its geocarpic nature of growth that the overall yield performance of groundnut is hindered by several biotic and abiotic stress factors. Multidimensional attempts were undertaken to combat these factors by developing superior groundnut varieties, modified with integral mechanism of tolerance/resistance; however this approach proved to be futile, owing to inferior pod and kernel quality. As a superior alternative, biotechnological intervention like transformation of foreign genes, either directly (biolistic) or via Agrobacterium , significantly aided in the development of advanced groundnut genotypes equipped with integral resistance against stresses and enhanced yield attributing traits. Several genes triggered by biotic and abiotic stresses, were detected and some of them were cloned and transformed as major parts of transgenic programmes. Application of modern molecular biological techniques, in designing biotic and abiotic stress tolerant/resistant groundnut varieties that exhibited mechanisms of resistance, relied on the expression of specific genes associated to particular stress. The genetically transformed stress tolerant groundnut varieties possess the potential to be employed as donor parents in traditional breeding programmes for developing varieties that are resilient to fungal, bacterial, and viral diseases, as well as to draught and salinity. The present review emphasizes on the retrospect and prospect of genetic transformation tools, implemented for the enhancement of groundnut varieties against key biotic and abiotic stress factors.

Transgenic Breeding Approaches for Improving Abiotic Stress Tolerance: Recent Progress and Future Perspectives

“…Genetic engineering may also allow us to overcome the reproductive barrier among different plant species [10]. Transgenic breeding efficiently improved crop production through genetic modification and improvements, with a short breeding phase [21]. Genome sequences are now available for different plant species (Arabidopsis, cucumber, tomato, rice, etc.…”

“…The identification of the candidate genes responsible for plant tolerance under different abiotic stresses is essential for developing transgenic crops with enhanced drought stress tolerance [12]. Once the genes controlling drought tolerance have been identified through QTL mapping, these genes can then be incorporated into the genetic background of any desirable cultivar using genetic engineering and hybridization with marker-assisted selection [10,21,23].…”

“…Plants are challenged by different kinds of abiotic stresses, such as salinity, drought, temperature, and heavy metals, which significantly limit crop production around the world [6]. Conventional breeding techniques have been used for crop improvements, which are now becoming constrained by the declining genetic resources of plants and time consuming [21]. There is a crucial need for efficient crop improvement strategies with novel genome editing techniques, such as CRISPR-Cas9 [69], which is easy, fast, efficient, and accurate in obtaining new genome edited crops ( Figure 5).…”

“…The ABA independent transcription factor (DREB1A) transgenic plants improve water use efficiency compared to wild type plants [84]. DREB1A distinctly stimulated the response of groundnut roots when exposed to water scarcity, wherein the stimulated roots grew significantly longer, especially in the deeper layers of soil [21]. Transgenic DREB1A groundnut (DREB1A genetically transformed by rd29 promoter), led to altering the root system in a consistent manner throughout the soil profile, thus increasing the root length density to facilitate the water extraction frequency [92].…”

“…Researchers confirmed that AtGBF3 regulated the combined stress tolerance by activating ABA-mediated signaling. They concluded that AtGBF3 significantly regulated combined drought and Pseudomonas syringae stresses [21,105].…”