Expression Patterns Analysis Of Gene For Maize In Response To Phosphorus Deficiency

Phosphorus (P) is one of essential macronutrients for plant growth and development, which is the important components of macro molecules in lives, such as nucleic acids, phospholipids. However available phosphorus in soil is low, which cannot satisfy the demand of plants to acquire the sufficient Pi. In the main area of corn production, lack of available phosphorus in soil has become one of the important factors for restricting yield of corn and increasing its production costs. Deficient phosphorus supplied in seedling will give rise to adverse effects, though provided enough phosphorus in the later stage. Therefore, the in-depth study of low-P tolerance mechanism of maize is of important theoretical significance and practical value.On the basis of screening many differentially expressed gene by chip the expression patterns of genes (glutathione S-transferase, MYB transcription factor, Acid phosphatase, Peroxidase ct al.) in response to low phosphate were investigated for maize 178 (P-efficient) and maize 9782 (P-sensitive) at 12h,24h,48h,72h and 96h after low phosphate stress with the normal phosphate as the control. The main results were as follows:1. Antioxidant response regulated by GST (glutathione sulfur transferase) in maize 178 under phosphorus stress was mainly in the early or middle period of stress. But maize 9782 was more sensitive than maize178 in the later stress time.2. The sensitive transcription of Zmmyb1 (MYB transcription factor) occurred at 12h after low phosphate stress. The expression was suppressed in maize 178. and the change was small, yet big in maize 9782.3. ACP (acid phosphatase) was not induced in maize 178 roots under phosphate stress, and the expression took on a large decreased trend. The expression of ACP was up-regulated in maize 9782, and maximum relative expression was reached at 12h. At the transcription level, its expression quantity in 9782 was less than maize 178 during the whole time.4. The expression of POD (peroxidase) showed a up-regulated single peak in maize 9782 under phosphate stress. And POD was suppressed in maize 178 with small variation.5. gln3 (glutamine synthelasc 3) was up-regulated in both of the two inbred maize lines. The high expression period of ghn3 in 178 fell behind 9782.6. The expression trend of CTP (CTP synthase) was notablely different between the two materials. CTP was down-regulated until 96h after low phosphate stress, at which the expression level resumed to control. CTP was obviously induced at 24h in 9782.7. The opposite changing of Ca (calnexin) expression of the two materials was showed that it was down-regulated with small-scope fluctuation in 178, and significantly up-regulated in 9782.8. The UBCc (Ubiquitin-conjugating enzyme domain containing protein) expression level of maize 9782 was significantly lower than that of maize 178, in which UBCc was induced twice at 12h and 72h respectively.The singularly up-regulated genes and down-regulated genes of maize 178 were GST26,gln3 and Zmmyhl. ACP,POD,CTP,Ca respectively. The expression of different processing periods and different genes was compared. It was GST26 and gln3 that played a major role during the early and late stress periods in maize 178 respectively. While the expression changes of maize 9782 is more complicated. During the stress period of maize roots, the variation of ACP,POD,Ca up-regulated expression were two-peak pattern curve. gln3 was only induced at 12h, which was similar to the expression pattern of UBCc. GST26,Zmmyb 1 and CTP were up-or down-regulated at the different stages of low phosphate stress. In maize 9782 gln3 was induced taking important parts in early stress phase, but POD showed its function in middle and late phases. The gene expression changes of maize 178 kept a steady level basically, which meant the phosphate deficiency taking a little effect on its roots. The high P-efficient maize 178 was initiatively more resistant in adverse situation, and the sensitive maize 9782 passively adapted to low phosphate stress.In a word, the expression of maize gene under different P stress time was analyzed. The detailed response of maize gene to low phosphorus stress was made clear. And the effect of phosphorus starvation on growth and metabolism of maize root was revealed. So the valuable information for searching genes possibly related to maize root phosphorus efficiency in phosphorus deficient environment was provided, which was of great importance for the excavation and use of phosphorus efficiency key genes and proposing strategies for crop molecular breeding of phosphorus efficiency.