Development And Test Cross Evaluation Of Transgentic Maize Germplasms For Shade Avoidance

Reasonable densities can improve the land utilization. It is the important technical measure to improve the yield of crops. When illumination is insufficient, the plant density is so high that increased the community competition due to its shade avoidance. It became serious when lodging, yield and quality got worse instead. Studies have shown that shade avoidance associated with plant light signal response. Plants accept environmental light signal receptor by Phytochrome protein (Phytochrome, Phy) pigment. Phy is divided into A, B, C, D, E and other different family. They can response to light signal wavelength, signal transduction pathways and regulate growth and development in different ways. In monocots, there are only three families:A, B and C. With exogenous or endogenous Phy gene into plants, by express or excessive expression suppression, they can change the sensitivity of the light signal, diminish shade avoidance response. As the result, they could be used to increase the planting density and the production. There are some successful experiences, such as rice, potato and other crops.This research of maize used inbred line 18-599 red callus and embryo as receptors, through the agrobacterium-mediated transformation and overexpression of endogenous PhyAl and PhyBl genes, trying to change light signal in maize, select maize germplasm of shade avoidance response, exploring new ways of increasing the reasonable density and further raising the yield of corn. The main results were as follows:1. In maize inbred B73 cDNA template, amplification PhyBl gene expression sequence, sequencing after verification to build monocotyledon constitutive expression vector pTF101.1-Ubi-PhyBl-T-nos. Use expression vector pTF101.1-Ubi-PhyBl-T-nos into agrobacterium EHA105 strains, again into maize inbred line 18-599 red callus, after screening, regeneration and PCR detection,12 strains of positive plants, among them 7 strains of normal strong gains.Use the expression vector pTF101.1-Ubi-PhyB1-T-nos into agrobacterium strains LBA4404, again into maize inbred line 18-599 red immature embryo, after screening, regeneration and PCR detection,2 strains of positive plants, normal strong gains.2. Use ZmPhyA1 and ZmPhyB1 genes of high generation of homozygous strain, and is contrast with receptor inbred lines 18-599 red, according to randomized block design in high and low two density under field phenotypic characterization, based on the differences of plant type traits, growth period, the transformation of evaluation to avoid the impact of the shadow of photosensitive pigment genes. The results show that with higher density, turn ZmPhyAl genetic strain of higher plant heigh, ZmPhyBl performance for plant height becomes short.3. Use ZmPhyAl and ZmPhyBl genes of high generation of homozygous strain, and is contrast with receptor inbred lines 18-599 red, respectively with eight inbred lines test cross, equipping 24 F1 hybrids, according to randomized block design field under the high and low density of two kinds of phenotypic characterization, according to the different growth period, plant type and yield traits, evaluation of phytochrome genes turned to avoid the impact of the shadow. Results show that in turn ZmPhyAl and ZmPhyBl genetic strain of equipping mixed species, plant height, panicle height, leaf number, the leaf length blade width were significantly greater than receptor inbred lines of mixed species,18-599 equipping only turn ZmPhyAl genetic strain inbred lines equipping mixed types of leaf Angle measurement and the receptor of mixed type of 18-599 equipping difference was not significant, but excessive expression of endogenous genes in different hybrid combination of the effects of plant-type traits is not the same.4. Turn ZmPhyAl genetic s train of mixed type of tasseling and equipping inbred lines 18-599 spinning and the receptor of mixed species difference was not significant, equipping and ZmPhyBl genetic strain of mixed type of equipping tasseling and silking stage than receptor inbred lines of mixed type of 18-599 equipping extremely significantly or significantly reduced.5. Analysis of variance showed that endogenous ZmPhyAl and ZmPhyBl gene transformation, for measuring mixed species of plant type, growth period and yield traits do have influence, excessive expression of endogenous phytochrome genes of maize of shade avoidance really does have an impact, but did not significantly reduce maize inbred lines and hybrids of shade avoidance response, especially in rainy and according to control plant height, position under the condition of high density planting vegetative organs high and moderate growth in the first place. On the one hand, specification of phytochrome gene function research remains to be further, on the other hand may also be causes such as gene silencing.The results showed that endogenous phytochrome gene expression can cause excessive plant type and the change of growth period traits, and have different performance under different planting density. However, different phytochrome gene function is not the same, to be the next step research.