Cassava is a staple food for people in tropical and subtropical regions. However, its cultivation faces challenges such as disease susceptibility, post-harvest spoilage, and low nutrient content. Breeding more resilient varieties is essential, yet this process is constrained by the plant’s low female-to-male flower ratio, which directly limits seed production in both natural and hybrid breeding.
In a study published in Journal of Plant Growth Regulation, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have revealed the intricate molecular mechanism controlled by the plant hormone cytokinin that leads to the formation of more female flowers in cassava.
"For decades, breeders have known that applying cytokinin, like the compound benzyladenine (BA), can promote female flowers," said PAN Bangzhen. "But the 'how' remained a black box. Our study opens this box, revealing a complex regulatory network that translates a hormonal signal into a developmental switch."
By performing comprehensive transcriptome sequencing on cassava inflorescence buds treated with BA, the researchers identified a widespread reprogramming of the plant's genetic activity. They found 2,749 differentially expressed genes, along with 95 long non-coding RNAs (lncRNAs), 46 circular RNAs (circRNAs), and 6 microRNAs (miRNAs) that were activated or suppressed.
The study indicated that lncRNAs help modulate hormone signaling and homeostasis, while miRNAs regulate key genes involved in cytokinin metabolism and stress responses. Strong correlations were found between circRNAs and their parent genes, which are involved in hormone transport and related processes, suggesting that circRNAs participate in feedback mechanisms to fine-tune cytokinin distribution within flower buds.
“Our study provides a theoretical guidance for understanding and manipulating cassava flower development and sex determination at the molecular level,” said PAN Bangzhen.
BA treatments promote female flower number in cassava plants. (Image by PAN Bangzhen)
Published: 23 October 2025
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