Brassinosteroids participate in many physiological processes in plants;however,their regulatory roles on the activities of the enzymes involved in dark phase of photosynthesis remains elusive.In this study,detached le...Brassinosteroids participate in many physiological processes in plants;however,their regulatory roles on the activities of the enzymes involved in dark phase of photosynthesis remains elusive.In this study,detached leaves and protoplasts of maize seedlings were treated with epi-brassinolide(EBR)and brassinazole followed by the determination of the contents of chlorophyll(a+b)and soluble sugars,and the activity of dark reaction enzymes and the expression of the relevant genes.The results showed that chlorophyll(a+b)content increased by 7.4%under 0.1μM EBR treatment for 48 h;furthermore,chlorophyll(a+b)content increased by 34%in detached leaves that were continuously soaked in brassinazole.In addition,the transcription levels of glyceraldehyde3-phosphate dehydrogenase subunit A(GAPA),cytoplasmic FBPase(cyFBPase),ribulose-1,5-bisphosphate carboxylase small subunit(rbcS),phosphoenolpyruvate carboxylase(PEPC),fructose-1,6-bisphosphatase(FBPase),Rubisco activaseβsubunit(RCAβ),ribulose-l,5-bisphosphate carboxylase large subunit(rbcL),and glutathione reductase(GR)were 96.8%,48.4%,79.3%,41%,85.6%,133.3%,68.8%,and 119.8%higher,respectively,in 0.1μM EBR than in the control group.The activity of RCA and Rubisco and soluble sugar content increased by 53.4%,28.7%,and 35.4%under 0.1μM EBR.Brassinazole inhibits the expression of these genes.However,the transcription level,protein content,and activity of some dark-reaction enzymes cannot be increased at the same time under EBR treatment.These results indicate that the effect of EBR on dark-reaction is mainly in transcription level.展开更多
Improving disease resistance is a primary objective in crop breeding.However,the signaling mechanisms governing disease resistance and yield are frequently controlled antagonistically,posing challenges in balancing cr...Improving disease resistance is a primary objective in crop breeding.However,the signaling mechanisms governing disease resistance and yield are frequently controlled antagonistically,posing challenges in balancing crop productivity and disease resistance.Prior research has shown that Brassinazole resistant 1(BZR1)enhances resistance to rice sheath blight(ShB)and increases tillering in rice.Here,we found that BZR1 interacts with NAC29 and NAC31,the primary transcription factors responsible for regulating the formation of the secondary cell wall.The interaction between NAC29 and NAC31 was demonstrated by yeast two-hybrid and bimolecular fluorescence complementation tests.The expression of NAC29 and NAC31 increased significantly in response to Rhizoctonia solani infection.The susceptibility of the nac29nac31 double mutant to ShB was increased,but the overexpression of NAC29 and NAC31 reduced susceptibility to ShB compared with the single mutants or wild-type plants.Like the bzr1-D,a BZR1 dominant negative mutant,NAC29 and NAC31 overexpressors increased tiller numbers.Co-expression of BZR1 and NAC29 or NAC31 enhanced cinnamyl alcohol dehydrogenase 8B(CAD8B)expression while inhibiting teosinte branched 1(TB1)expression to a greater extent than the expression of BZR1 alone.Furthermore,the expression level of CAD8B was elevated in NAC29-OX and NAC31-OX plants,but the expression level of TB1 was reduced in NAC29-OX and NAC31-OX plants compared to the wild-type plants.The results showed that BZR1-NAC29-NAC31 improves rice resistance and tillering by controlling the expression of CAD8B and TB1,respectively.These findings offer valuable targets for breeding that can avoid the trade-off between growth and defense.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31771702 and 31571682).
文摘Brassinosteroids participate in many physiological processes in plants;however,their regulatory roles on the activities of the enzymes involved in dark phase of photosynthesis remains elusive.In this study,detached leaves and protoplasts of maize seedlings were treated with epi-brassinolide(EBR)and brassinazole followed by the determination of the contents of chlorophyll(a+b)and soluble sugars,and the activity of dark reaction enzymes and the expression of the relevant genes.The results showed that chlorophyll(a+b)content increased by 7.4%under 0.1μM EBR treatment for 48 h;furthermore,chlorophyll(a+b)content increased by 34%in detached leaves that were continuously soaked in brassinazole.In addition,the transcription levels of glyceraldehyde3-phosphate dehydrogenase subunit A(GAPA),cytoplasmic FBPase(cyFBPase),ribulose-1,5-bisphosphate carboxylase small subunit(rbcS),phosphoenolpyruvate carboxylase(PEPC),fructose-1,6-bisphosphatase(FBPase),Rubisco activaseβsubunit(RCAβ),ribulose-l,5-bisphosphate carboxylase large subunit(rbcL),and glutathione reductase(GR)were 96.8%,48.4%,79.3%,41%,85.6%,133.3%,68.8%,and 119.8%higher,respectively,in 0.1μM EBR than in the control group.The activity of RCA and Rubisco and soluble sugar content increased by 53.4%,28.7%,and 35.4%under 0.1μM EBR.Brassinazole inhibits the expression of these genes.However,the transcription level,protein content,and activity of some dark-reaction enzymes cannot be increased at the same time under EBR treatment.These results indicate that the effect of EBR on dark-reaction is mainly in transcription level.
基金supported by the National Natural Science Foundation of China(31901857,32372482,and 32072406)the Postdoctoral Research Foundation of China(2022M712203)+1 种基金the Department of Education of Liaoning Province(LJKZ0641 and JYTYB2024060)the Natural Science Foundation of Liaoning Province(2021-MS-223).
文摘Improving disease resistance is a primary objective in crop breeding.However,the signaling mechanisms governing disease resistance and yield are frequently controlled antagonistically,posing challenges in balancing crop productivity and disease resistance.Prior research has shown that Brassinazole resistant 1(BZR1)enhances resistance to rice sheath blight(ShB)and increases tillering in rice.Here,we found that BZR1 interacts with NAC29 and NAC31,the primary transcription factors responsible for regulating the formation of the secondary cell wall.The interaction between NAC29 and NAC31 was demonstrated by yeast two-hybrid and bimolecular fluorescence complementation tests.The expression of NAC29 and NAC31 increased significantly in response to Rhizoctonia solani infection.The susceptibility of the nac29nac31 double mutant to ShB was increased,but the overexpression of NAC29 and NAC31 reduced susceptibility to ShB compared with the single mutants or wild-type plants.Like the bzr1-D,a BZR1 dominant negative mutant,NAC29 and NAC31 overexpressors increased tiller numbers.Co-expression of BZR1 and NAC29 or NAC31 enhanced cinnamyl alcohol dehydrogenase 8B(CAD8B)expression while inhibiting teosinte branched 1(TB1)expression to a greater extent than the expression of BZR1 alone.Furthermore,the expression level of CAD8B was elevated in NAC29-OX and NAC31-OX plants,but the expression level of TB1 was reduced in NAC29-OX and NAC31-OX plants compared to the wild-type plants.The results showed that BZR1-NAC29-NAC31 improves rice resistance and tillering by controlling the expression of CAD8B and TB1,respectively.These findings offer valuable targets for breeding that can avoid the trade-off between growth and defense.
