Arabidopsis abcbl abcb19 double mutants defective in the auxin transporters ABCB1/PGP1 and ABCB19/PGP19 are altered in stamen elongation, anther dehiscence and pollen maturation. To assess the contribution of these tr...Arabidopsis abcbl abcb19 double mutants defective in the auxin transporters ABCB1/PGP1 and ABCB19/PGP19 are altered in stamen elongation, anther dehiscence and pollen maturation. To assess the contribution of these transporters to stamen development we performed phenotypic, histological analyses, and in situ hybridizations on abcbl and abcbl9 single mutant flowers. We found that pollen maturation and anther dehiscence are precocious in the abcbl but not in the abcb19 mutant. Accordingly, endothecium ligniflcation is altered only in abcbl anthers. Both abcbl and abcb1 abcb19 stamens also show altered early development, with asynchronous anther Iocules and a multilayer tapetum. DAPI staining showed that the timing of meiosis is asynchronous in abcbl abcb19 anther Iocules, while only a small percentage of pollen grains are non- viable according to Alexander＇s staining. In agreement, TAM （TARDY ASYNCHRONOUS MEIOSIS）, as well as BAM2 （BARELY ANY MERISTEM）involved in tapetal cell development--areoverexpressed in abcbl abcb19 young flower buds. Corre- spondingly, ABCB1 and ABCB19 mRNA localization supports the observed phenotypes of abcbl and abcbl abcb19 mutant anthers. In conclusion, we provide evidence that auxin transport plays a significant role both in early and late stamen development： ABCB1 plays a major role during anther development, while ABCB19 has a synergistic role.展开更多
Anther dehiscence is a crucial event in plant reproduction,tightly regulated and dependent on the lignification of the anther endothecium.In this study,we investigated the rapid lignification process that ensures time...Anther dehiscence is a crucial event in plant reproduction,tightly regulated and dependent on the lignification of the anther endothecium.In this study,we investigated the rapid lignification process that ensures timely anther dehiscence in Arabidopsis.Our findings reveal that endothecium lignification can be divided into two distinct phases.During Phase Ⅰ,lignin precursors are synthesized without polymerization,while Phase Ⅱ involves simultaneous synthesis of lignin precursors and polymerization.The transcription factors MYB26,NST1/2,and ARF17 specifically regulate the pathway responsible for the synthesis and polymerization of lignin monomers in Phase Ⅱ.MYB26-NST1/2 is the key regulatory pathway responsible for endothecium lignification,while ARF17 facilitates this process by interacting with MYB26.Interestingly,our results demonstrate that the lignification of the endothecium,which occurs within approximately 26 h,is much faster than that of the vascular tissue.These findings provide valuable insights into the regulation mechanism of rapid lignification in the endothecium,which enables timely anther dehiscence and successful pollen release during plant reproduction.展开更多
基金partially supported by a research grant from MIUR (PRIN) to P.C. and M.C.a research grant to M.C. from the Italian Ministry of Foreign Affairs (Direzione Generale per la Promozione del Sistema Paese, Unità per la cooperazione scientifica e tecnologica bilaterale e multilaterale)
文摘Arabidopsis abcbl abcb19 double mutants defective in the auxin transporters ABCB1/PGP1 and ABCB19/PGP19 are altered in stamen elongation, anther dehiscence and pollen maturation. To assess the contribution of these transporters to stamen development we performed phenotypic, histological analyses, and in situ hybridizations on abcbl and abcbl9 single mutant flowers. We found that pollen maturation and anther dehiscence are precocious in the abcbl but not in the abcb19 mutant. Accordingly, endothecium ligniflcation is altered only in abcbl anthers. Both abcbl and abcb1 abcb19 stamens also show altered early development, with asynchronous anther Iocules and a multilayer tapetum. DAPI staining showed that the timing of meiosis is asynchronous in abcbl abcb19 anther Iocules, while only a small percentage of pollen grains are non- viable according to Alexander＇s staining. In agreement, TAM （TARDY ASYNCHRONOUS MEIOSIS）, as well as BAM2 （BARELY ANY MERISTEM）involved in tapetal cell development--areoverexpressed in abcbl abcb19 young flower buds. Corre- spondingly, ABCB1 and ABCB19 mRNA localization supports the observed phenotypes of abcbl and abcbl abcb19 mutant anthers. In conclusion, we provide evidence that auxin transport plays a significant role both in early and late stamen development： ABCB1 plays a major role during anther development, while ABCB19 has a synergistic role.
基金supported by grants from the National Key R&D Program of China (2022YFF1003502)the National Natural Science Foundation of China (31930009, 31900165)the Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-02-E00006)。
文摘Anther dehiscence is a crucial event in plant reproduction,tightly regulated and dependent on the lignification of the anther endothecium.In this study,we investigated the rapid lignification process that ensures timely anther dehiscence in Arabidopsis.Our findings reveal that endothecium lignification can be divided into two distinct phases.During Phase Ⅰ,lignin precursors are synthesized without polymerization,while Phase Ⅱ involves simultaneous synthesis of lignin precursors and polymerization.The transcription factors MYB26,NST1/2,and ARF17 specifically regulate the pathway responsible for the synthesis and polymerization of lignin monomers in Phase Ⅱ.MYB26-NST1/2 is the key regulatory pathway responsible for endothecium lignification,while ARF17 facilitates this process by interacting with MYB26.Interestingly,our results demonstrate that the lignification of the endothecium,which occurs within approximately 26 h,is much faster than that of the vascular tissue.These findings provide valuable insights into the regulation mechanism of rapid lignification in the endothecium,which enables timely anther dehiscence and successful pollen release during plant reproduction.
