In a new study published in Horticulture Research, a team led by Professor Tongming Yin at the State Key Laboratory for Tree Genetics and Breeding of Nanjing Forestry University, has proposed a novel role for MSL-lncRNAs in causing sex lability in female poplars. This work provides fresh insights into the complex genetic mechanisms behind the labile expression of sex in various Populus species.
Flowering plants exhibit remarkable diversity in their sexual reproduction, and one-third of angiosperms produce unisexual rather than bisexual flowers. Among these, poplar species are typically dioecious, meaning individual trees bear either male or female flowers. However, the phenomenon of sex lability—shifts between sexes or the formation of opposite sexual flowers on typically male or female plants—has often been reported in Populus species. The underlying genetic mechanism for this, however, remained unclear until now.
The research team focused their efforts on MSL, a gene found in the genome of Populus deltoides. Their study revealed that both strands of MSL contain multiple cis-activating elements, leading to the production of long non-coding RNAs (lncRNAs) that promote maleness.
Interestingly, while female P. deltoides do not possess the male-specific MSL gene, the team detected a large number of partial sequences highly similar to this gene in the genomes of various sequenced poplars. When these partial sequences were heterologously expressed in Arabidopsis, a model plant, they promoted maleness. The research team observed transformed lines with variations in the stamen structure, including flowers with six long stamens, or stamens bearing multiple anthers, among others.
Based on these findings, the team proposed a molecular model for sex lability in female poplars. In this model, activated transcription of MSL homologous sequences leads to female lability but does not cause male lability.
This study offers a unique perspective for a better understanding of female sex lability in poplar, while the results suggest that if these maleness promoters were to be expressed in female poplars, they would lead to sex lability, providing a new avenue to investigate the genetic dynamics of sex expression in plants. This research also adds a significant piece to the puzzle of plant sexual reproduction and opens up new possibilities for studying and manipulating sex expression in plants. The team's findings will help inform future research in this area and potentially contribute to more effective breeding strategies in forestry.
Flowering plants exhibit remarkable diversity in their sexual reproduction, and one-third of angiosperms produce unisexual rather than bisexual flowers. Among these, poplar species are typically dioecious, meaning individual trees bear either male or female flowers. However, the phenomenon of sex lability—shifts between sexes or the formation of opposite sexual flowers on typically male or female plants—has often been reported in Populus species. The underlying genetic mechanism for this, however, remained unclear until now.
The research team focused their efforts on MSL, a gene found in the genome of Populus deltoides. Their study revealed that both strands of MSL contain multiple cis-activating elements, leading to the production of long non-coding RNAs (lncRNAs) that promote maleness.
Interestingly, while female P. deltoides do not possess the male-specific MSL gene, the team detected a large number of partial sequences highly similar to this gene in the genomes of various sequenced poplars. When these partial sequences were heterologously expressed in Arabidopsis, a model plant, they promoted maleness. The research team observed transformed lines with variations in the stamen structure, including flowers with six long stamens, or stamens bearing multiple anthers, among others.
Based on these findings, the team proposed a molecular model for sex lability in female poplars. In this model, activated transcription of MSL homologous sequences leads to female lability but does not cause male lability.
This study offers a unique perspective for a better understanding of female sex lability in poplar, while the results suggest that if these maleness promoters were to be expressed in female poplars, they would lead to sex lability, providing a new avenue to investigate the genetic dynamics of sex expression in plants. This research also adds a significant piece to the puzzle of plant sexual reproduction and opens up new possibilities for studying and manipulating sex expression in plants. The team's findings will help inform future research in this area and potentially contribute to more effective breeding strategies in forestry.