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: External treatment with ethylene had indicated earlier that this hormone is the main factor controlling sex determination in Cucurbita pepo. Up to now, however, there was no genetic evidence that supported the relationship between ethylene production, or perception, and sexual expression in this species. Here we demonstrate that the extreme male phenotype of the Vegetable Spaghetti (Veg) inbred line of C. pepo subspecies pepo is determined by a major gene that confers reduced ethylene sensitivity in plants. The production of female flowers in the Veg line is very delayed and reduced with respect to the contrasting Bolognese (Bog) line, ranging between 5 and 35% of female flowers per plant. This enhanced maleness trait segregates as a single gene in the F2 and backcross (BC) generations, and co-segregates with a weak ethylene-insensitive phenotype in the F2 population, suggesting that the gene responsible for the Veg phenotype could be the result of a mutation in a receptor or response gene for ethylene. Although the etiolated seedlings of the Veg line, and the most androecious plants in the F2 generation, produce more ethylene than those of the contrasting line, they are less sensitive to this hormone, as indicated by a weaker triple response and a delayed abscission of ethylene-treated male flowers. Given that the sexual phenotype of F2 plants is correlated with ethylene sensitivity, with the more sensitive plants producing the higher number of female flowers, our results demonstrate that the ethylene response is directly involved in the control of sex determination in C. pepo. It regulates the induction of female flower production, and therefore the extension of the initial phase of development in which the plant produces only male flowers, as well as the number of female flowers per plant. Keywords Cucurbita pepo -Sex expression-Ethylene production-Ethylene sensitivityJournal of Plant Growth Regulation 03/2009; 29(1):73-80. DOI:10.1007/s00344-009-9116-5 · 2.06 Impact Factor
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ABSTRACT: Efforts in hybrid breeding have made this technology one of the main factors contributing to the substantial global rise in agricultural output over the last few decades. For hybrid breeding, an efficient pollination control system is necessary to avoid the unwanted self-pollination or sib-pollination of the female parental line. This review will provide a historical overview of pollination control systems and their use in hybrid crop breeding. We outline the prerequisites for commercial hybrid breeding and summarize the most important non-biological and biological technologies. Our main focus is on hybrid systems that are based on genetically engineered plants. We describe their suitability for pollination control, propagation of the male-sterile crossing partner, fertility restoration and mixed planting. Additionally, we report on the latest findings in the development of inducible sterility systems and various technologies that enable pollination control via metabolic engineering. We discuss the pros and cons of the different pollination control strategies. KeywordsHybrid breeding–Pollination control–Male sterility–Transgenic plants–Metabolic engineeringMolecular Breeding 04/2011; 27(4):417-437. DOI:10.1007/s11032-011-9555-0 · 2.28 Impact Factor
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ABSTRACT: Ethylene (ET) is a notable signaling molecule in higher plants. In the year 1993 the ET receptor gene, ETR1, was identified; this ETR1 receptor protein being the first plant hormone receptor to be isolated. It is striking that there are six ET receptors in tomato instead of five in Arabidopsis, the two best-known signaling-model systems. Even though over the last few years great progress has been made in elucidating the genes and proteins involved in ET signaling, the complete pathway remains to be established. The present review examines the most representative successive advances that have taken place in this millennium in terms of the signaling pathway of ET, as well as the implications of the signaling in the reproductive organs of plants (i.e., flowers, fruits, seeds and pollen grains). A detailed comparative study is made on the advances in knowledge in the last decade, showing how the characterization of ET signaling provides clues for understanding how higher plants regulate their ET sensitivity. Also, it is indicated that ET signaling is at present sparking interest within phytohormonal molecular physiology and biology, and it is explained why several socio-economic aspects (flowering and fruit ripening) are undoubtedly involved in ET physiology.Plant signaling & behavior 10/2006; 1(5):231-42. DOI:10.4161/psb.1.5.3389