Anther-specific expression of mutated melon ethylene receptor gene Cm-ERS1/H70A affected tapetum degeneration and pollen grain production in transgenic tobacco plants
ABSTRACT To develop a new system for inducible male sterility without any modification of the floral architecture in tobacco plants, a mutated ethylene receptor gene Cm-ERS1/H70A was fused either to the tobacco Nin88 promoter known to function mainly in the tapetum and microspore or to the CaMV 35S promoter known to be a constitutive promoter. The fusion genes pNin88::Cm-ERS1/H70A and p35S::Cm-ERS1/H70A were introduced in tobacco plants, which generated two independent transformants. Transformants with 35S::Cm-ERS1/H70A produced less normal pollen and had modified floral architecture while those with Nin88::Cm-ERS1/H70A produced less normal pollen without modification of floral architecture. Histological observations of anthers at stage 2 showed that tapetum degeneration in NH70A #8 and H70A #2 transformants occurred later than in wild types, strongly indicating that the expression of the mutated gene was involved in this delay. These results suggest that the tapetum-specific expression of a mutated ethylene receptor gene is a potential strategy for inducing male sterility in transgenic plants.
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ABSTRACT: The past two decades have been rewarding in terms of deciphering the ethylene signal transduction and functional validation of the ethylene receptor and downstream genes involved in the cascade. Our knowledge of ethylene receptors and its signal transduction pathway provides us a robust platform where we can think of manipulating and regulating ethylene sensitivity by the use of genetic engineering and making transgenic. This review focuses on ethylene perception, receptor mediated regulation of ethylene biosynthesis, role of ethylene receptors in flower senescence, fruit ripening and other effects induced by ethylene. The expression behavior of the receptor and downstream molecules in climacteric and non climacteric crops is also elaborated upon. Possible strategies and recent advances in altering the ethylene sensitivity of plants using ethylene receptor genes in an attempt to modulate the regulation and sensitivity to ethylene have also been discussed. Not only will these transgenic plants be a boon to post-harvest physiology and crop improvement but, it will also help us in discovering the mechanism of regulation of ethylene sensitivity.Plant signaling & behavior 07/2012; 7(7):827-46. DOI:10.4161/psb.20321
Article: Engineered Male Sterility[Show abstract] [Hide abstract]
ABSTRACT: The agricultural exploitation of hybrid crop varieties has enabled enormous increases in food productivity through increased uniformity and hybrid vigour. Because of hybrid vigour, or heterosis , these crops are characterized by an increased resistance to disease and enhanced performance in different environments when comparing the heterozygous hybrid progeny (called F1 hybrids) to the homozygous parents. The generation of male sterility, mainly nucleus -encoded, is the basis of new, reliable, and cost-effective pollination control systems for genetic engineering that have been developed during the past decade. The propagation of male-sterile female parent lines is an important aspect for the successful application of these systems in large-scale hybrid seed production. This article describes the development and use of transgenic engineered plants.
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ABSTRACT: Molecular stacking enables multiple traits to be effectively engineered in crops using a single vector. However, the co-existence of distinct plant promoters in the same transgenic unit might, like their mammalian counterparts, interfere with one another. In this study, we devised a novel approach to investigate enhancer-promoter and promoter-promoter interactions in transgenic plants and demonstrated that three of four flower-specific enhancer/promoters were capable of distantly activating a pollen- and stigma-specific Pps promoter (fused to the cytotoxic DT-A gene) in other tissues, as revealed by novel tissue ablation phenotypes in transgenic plants. The NtAGI1 enhancer exclusively activated stamen- and carpel-specific DT-A expression, thus resulting in tissue ablation in an orientation-independent manner; this activation was completely abolished by the insertion of an enhancer-blocking insulator (EXOB) between the NtAGI1 enhancer and Pps promoter. Similarly, AGL8 and AP1Lb1, but not AP1La, promoters also activated distinct tissue-specific DT-A expression and ablation, with the former causing global growth retardation and the latter ablating apical inflorescences. While the tissue specificity of the enhancer/promoters generally defined their activation specificities, the strength of their activity in particular tissues or developmental stages appeared to determine whether activation actually occurred. Our findings provide the first evidence that plant-derived enhancer/promoters can distantly interact/interfere with one another, which could pose potential problems for the tissue-specific engineering of multiple traits using a single-vector stacking approach. Therefore, our work highlights the importance of adopting enhancer-blocking insulators in transformation vectors to minimize promoter-promoter interactions. The practical and fundamental significance of these findings will be discussed.Plant Biotechnology Journal 06/2014; 12(7). DOI:10.1111/pbi.12203 · 5.68 Impact Factor