Reseach On The Expression Of Plastid Terminal Oxidase And Related Genes In Soybean Seedling Under Different Light Qualities

In the context of maize-soybean relay strip systems in southern places, we select two soybean varieties which are strong shade tolerance "Gongxuan 1" and low shade tolerance "Nan 032-4" as experimental materials, and take the fluorescent lamps and LED lamps as light sources to do this research. On one hand, we determine the expression levels of PTOX protein and its gene and related functional genes under four light qualities of white, red, blue, red to far red; on the other hand, we determine the expression level of PTOX protein and its gene and related functional genes and photosynthetic characters, chlorophyll fluorescence characteristics, pigment contents under light simulation of intercropping(red: blue:far red=1:1:0.88) and net cropping(red:blue:far red=1:1:0.68). The main results are as follows:1. Under whit light after protect form lights, PTOX, PGR5, PDS, ZDS of both soybean varieties increase gradually with its maximum after 120 minutes, AOX1, AOX2a, AOX2b of two soybean varieties increase to the maximum in 30 to 60 minutes then go down, both two soybean varieties gene expression levels of NDH-H and RbcS are unchangeable. Change trends of all gene expression levels under red light are the same with them under white light except gene transcripts of PDS in Gongxuan 1 remains the same in 150 minutes. Red light to far red light irradiation, all gene transcripts of PTOX, PGR5, AOX1, AOX2a, AOX2b, PDS, ZDS turn down rapidly, while NDH-H and RbcS do not change. Gongxuan 1 under blue light, gene expression levels of PTOX, PGR5, AOX1, PDS, ZDS increase gradually with its maximum after 120 minutes, AOX2a, AOX2b of two soybean varieties increase to the maximum in 30 to 60 minutes then go down, NDH-H and RbcS are unchangeable. Nan 032-4 under blue light, gene transcripts of PTOX, PGR5 increase gradually with its maximum after 120 minutes, while NDH-H, AOX1, AOX2a, AOX2b, PDS, ZDS, RbcS remaining the same. The PTOX protein level of two soybean varieties increases under white, red and blue light, and it decreases under far red light. The variation of PTOX level is higher in different degrees in seedling leaves of Gongxuan 1 than it in Nan 032-4.2. Compared with the light simulation of net cropping, under the light simulation of intercropping, the gene transcripts of two soybean varieties of PTOX and PGR5 decrease while PDS and ZDS increase; gene expression levels of AOX1, AOX2a increase while A0X2b remains unchanged in seedling leaves of Gongxuan 1, gene expression level of A0X1 decreases while AOX2a stays unchangeable, gene expression level of AOX2b increases. The protein level of PTOX is lower in seedling leaves under the light simulation of intercropping than it under the light simulation of net cropping. The relative gene transcripts of PTOX are extremely significant higher in seedling leaves of Gongxuan 1 than them in Nan 032-4.3. Compared with the light simulation of net cropping, under the light simulation of intercropping, seedlings of two soybean varieties have a lower Gs, Tr and a higher Ci; which also have a higher Fo, ΦPS Ⅱ and a lower Fv/Fm, Qp, NPQ, ETR and they have a higher Chla, Chl b, total chlorophyll content, a lower Chla/b, Car content. Parameters are a bit better in seedling leaves of Gongxuan 1 than them in Nan 032-4.By analysis of the results above we found that plant photosynthesis of soybean is improved by regulation on PTOX and the related functional genes under different light environment. Compared with the low shade tolerant soybean Nan 032-4, the mediation ability of strong shade tolerance Gongxuan 1 on photosynthetic electron transfer is stronger, which PTOX participate and play a certain role in it.