Study On Stress Tolerance Of Solanum Tuberosum VacINV1-RNAi Lines

vacuolar acid invertase?vacINV?is one of the key enzymes in sucrose metabolism that irreversibly catalyzes the decomposition of sucrose into glucose and fructose in plants.There are two vacINV genes in potato?Solanum tuberosum L.?,and vacINV1 is mainly involved in regulation reducing sugars accumulation when tubers are stored at low temperature.However,It is unclear whether vacINV1 is involved in regulating abiotictolerance in potato..In this paper,three lines of vacINV1-RNAi transgenic potato cultivar“Atlantic”,which is down-regulated by vacINV1 gene,were used as materials to analyze the differences of tolerance between transgenic plants and non-transgenic potato plants when faced with low-temperature,drought,and high-salt stresses.Specially,the differences in the physiology and biochemistry response to cold stress between the transgenic plants and the non-transgenic potato plants were emphasically analyzed.The mechanism of the vacINV1 gene in freezing tolerance of potato plants was discussed.The result is as follows:?1?Three vacINV1-RNAi transgenic lines and non-transgenic potato variety“Atlantic”were treated at-2°C,the RNAi-3 lines were wilted at 2 h after low temperature treatment,and RNAi-1 and RNAi-2 strains were wilted at 2.5 h,whereas the non-transgenic plants began to wilt at 7 h.Thus,it was initially demonstrated that the vacINV1-RNAi strain was less tolerant to cold than non-transgenic plants.?2?Drought treatment of three vacINV1-RNAi transgenic lines and non-transgenic potato variety"Atlantic",non-transgenic plants began to wilt within 6 days of drought treatment,transgenic lines RNAi-2,RNAi-3 and RNAi-1 respectively on the 7d,11d,and 12d.Thus,the drought tolerance of three vacINV1-RNAi transgenic lines was higher than that of non-transgenic potato plants.?3?0,25,50,and 75 mmol/L NaC l solid MS media were used to culture three vacINV1-RNAi transgenic lines and non-transgenic potato varieties“Atlantic”tissue culture seedlings for 30 days,the transgenic and non-transgenic lines was no significant difference in plant height and the number of root.This shows that the three vacINV1-RN Ai transgenic lines have no significant difference in tolerance to salt stress and non-transgenic genes.?4?The physiological and biochemical responses to cold stress of the three vacINV1-RNAi transgenic lines and the non-transgenic potato“Atlantic”were significantly different.After low temperature treatment,the three vacINV1-RNAi transgenic lines showed significantly higher electrical conductivity,O₂.^-and H₂O₂ content than non-transgenic plants,and their SOD and APX activity and proline content were significantly lower than non-transgenic plants.Thus,the reduction of SOD and APX activity and proline content may be one of the main reasons for the increase of their electrical conductivity,O2.^-and H₂O₂content,that is,low temperature tolerance is reduce in potato vacINV1-RNAi transgenic lines??5?The sucrose metabolism of vacINV1-RN Ai strains was significantly different from that of non-transgenic potato plants before and after cryogenic treatment.The vacuolar acid invertase activity of the three vacINV1-RNAi transgenic lines before low temperature treatment was significantly lower than that of the non-transgenic plants,but there was no significant difference after low temperature treatment;the activities of sucrose synthetase in the three vacINV1-RNAi transgenic lines were treated at low temperature Afterwards,it was significantly lower than non-transgenic plants;low temperature treatment resulted in increased sucrose content in the three vacINV1-RNAi transgenic lines and decreased sucrose content in the non-transgenic plants.This suggests that the difference in sucrose metabolism caused by decreased expression of vacINV1 may be a cause of decreased tolerance to low temperature tolerance of potato vacINV1-RNAi transgenic lines.In summary,compared with non-transgenic plants,the vacINV1-RNAi transgenic lines have lower cold tolerance and higher drought tolerance,so vacINV1 is involved in the regulation of potato cold tolerance and drought tolerance.Under cold stress treatment,compared with non-transgenic potato plants,vacuolar acid invertase activity of vacINV1-RNAi transgenic lines was reduced,resulting in differences in sucrose-associated metabolism,affecting the accumulation of proline at low temperatures and the activities of SOD and APX,As a result,the conductivity of vacINV1-RNAi strain,the content o f O2^-.and H₂O₂ increased,and the low-temperature tolerance decreased.