The effects of NaCl salinity and NO^-3 on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl （1, 150, 300, and 450 ...The effects of NaCl salinity and NO^-3 on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl （1, 150, 300, and 450 mmol L^-1） and three NO^-3 levels （0.05, 5, and 10 mmol L^-1） in solution culture for 30 d. Addition of NO^-3 at 10 mmol L^-1 significantly improved the shoot （P 〈 0.001） and root （P 〈 0.001） growth and the promotive effect of NO^-3 was more pronounced on root dry weight despite the high NaCl concentration in the culture solution, leading to a significant increase in the root：shoot ratio （P 〈 0.01）. Lateral root length, but not primary root length, considerably increased with increasing NaCl salinity and NO^-3 levels （P 〈 0.001）, implying that Na^＋ and NO3^- in the culture solution simultaneously stimulated lateral root growth. Concentrations of Na^＋ in plant tissues were also significantly increased by higher NaCl treatments （P 〈 0.001）. At 10 mmol L^-1 NO^-3, the concentrations of NO^-3 and total nitrogen and nitrate reductase activities in the roots were remarkably reduced by increasing salinity （P 〈 0.001）, but were unaffected in the shoots. The results indicated that the fine lateral root development and effective nitrogen uptake of the shoots might contribute to high salt tolerance of S. physophora under adequate NO^-3 supply.展开更多
AUXIN RESPONSE FACTOR 7(ARF7)-mediated auxin signaling plays a key role in lateral root(LR)development by regulating downstream LATERAL ORGAN BOUNDARIES DOMAIN(LBD)transcription factor genes,including LBD16,LBD18,and ...AUXIN RESPONSE FACTOR 7(ARF7)-mediated auxin signaling plays a key role in lateral root(LR)development by regulating downstream LATERAL ORGAN BOUNDARIES DOMAIN(LBD)transcription factor genes,including LBD16,LBD18,and LBD29.LBD proteins are believed to regulate the transcription of downstream genes as homodimers or heterodimers.However,whether LBD29 forms dimers with other proteins to regulate LR development remains unknown.Here,we determined that the Arabidopsis thaliana(L.)Heynh.MYB transcription factors MYB2 and MYB108 interact with LBD29 and regulate auxin-induced LR development.Both MYB2 and MYB108 were induced by auxin in an ARF7-dependent manner.Disruption of MYB2 by fusion with an SRDX domain severely affected auxin-induced LR formation and the ability of LBD29 to induce LR development.By contrast,overexpression of MYB2 or MYB108 resulted in greater LR numbers,except in the lbd29 mutant background.These findings underscore the interdependence and importance of MYB2,MYB108,and LBD29 in regulating LR development.In addition,MYB2–LBD29 and MYB108–LBD29 complexes promoted the expression of CUTICLE DESTRUCTING FACTOR 1(CDEF1),a member of the GDSL(Gly-Asp-Ser-Leu)lipase/esterase family involved in LR development.In summary,this study identified MYB2–LBD29 and MYB108–LBD29 regulatory modules that act downstream of ARF7 and intricately control auxin-mediated LR development.展开更多
基金Supported by the Key Technology Program of the Xinjiang Uygur Autonomous Region, China (No.200733144-1)the Knowledge Innovation Project of the Chinese of Academy of Sciences (No.KSCX2-YW-N-41)
文摘The effects of NaCl salinity and NO^-3 on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl （1, 150, 300, and 450 mmol L^-1） and three NO^-3 levels （0.05, 5, and 10 mmol L^-1） in solution culture for 30 d. Addition of NO^-3 at 10 mmol L^-1 significantly improved the shoot （P 〈 0.001） and root （P 〈 0.001） growth and the promotive effect of NO^-3 was more pronounced on root dry weight despite the high NaCl concentration in the culture solution, leading to a significant increase in the root：shoot ratio （P 〈 0.01）. Lateral root length, but not primary root length, considerably increased with increasing NaCl salinity and NO^-3 levels （P 〈 0.001）, implying that Na^＋ and NO3^- in the culture solution simultaneously stimulated lateral root growth. Concentrations of Na^＋ in plant tissues were also significantly increased by higher NaCl treatments （P 〈 0.001）. At 10 mmol L^-1 NO^-3, the concentrations of NO^-3 and total nitrogen and nitrate reductase activities in the roots were remarkably reduced by increasing salinity （P 〈 0.001）, but were unaffected in the shoots. The results indicated that the fine lateral root development and effective nitrogen uptake of the shoots might contribute to high salt tolerance of S. physophora under adequate NO^-3 supply.
基金supported by the National Natural Science Foundation of China(32070319 and 32370330)Shandong Natural Science Foundation(ZR2021QC067)。
文摘AUXIN RESPONSE FACTOR 7(ARF7)-mediated auxin signaling plays a key role in lateral root(LR)development by regulating downstream LATERAL ORGAN BOUNDARIES DOMAIN(LBD)transcription factor genes,including LBD16,LBD18,and LBD29.LBD proteins are believed to regulate the transcription of downstream genes as homodimers or heterodimers.However,whether LBD29 forms dimers with other proteins to regulate LR development remains unknown.Here,we determined that the Arabidopsis thaliana(L.)Heynh.MYB transcription factors MYB2 and MYB108 interact with LBD29 and regulate auxin-induced LR development.Both MYB2 and MYB108 were induced by auxin in an ARF7-dependent manner.Disruption of MYB2 by fusion with an SRDX domain severely affected auxin-induced LR formation and the ability of LBD29 to induce LR development.By contrast,overexpression of MYB2 or MYB108 resulted in greater LR numbers,except in the lbd29 mutant background.These findings underscore the interdependence and importance of MYB2,MYB108,and LBD29 in regulating LR development.In addition,MYB2–LBD29 and MYB108–LBD29 complexes promoted the expression of CUTICLE DESTRUCTING FACTOR 1(CDEF1),a member of the GDSL(Gly-Asp-Ser-Leu)lipase/esterase family involved in LR development.In summary,this study identified MYB2–LBD29 and MYB108–LBD29 regulatory modules that act downstream of ARF7 and intricately control auxin-mediated LR development.
