The long 5′ untranslated region (5′UTR) exhibits enhancer activity in translation of rice OsMac3 mRNA. In this report, we describe elements of OsMac3 5′UTR that may be responsible for its enhancer activity, including a long uORF and several secondary structure elements. OsMac3 5′UTR can be dissected into three stem-loop structures SL1, small SL and SL2, where the uORF starts within SL1 and ends within SL2. As expected, uORF inhibits translation of downstream ORF since deletion of the uORF AUG or the SL1 stem-loop increases translation by approximately two-fold. Thus, the 158 nt 3′ region of the 5′UTR lacking SL1 together with the AUG uORF, which has significant enhancer activity, was named dMac3. We investigated two critical regions within dMac3 mRNA that influence its translation: SL2, which destabilization potentially decreases translation activity, and another 13 nt located downstream of SL2. We further confirmed that dMac3 promotes mRNA translation initiation in an in vitro translation system and during transient expression in either cultured cells or Nicotiana benthamiana leaves. Thus, the dMac3 5′UTR is a useful tool for efficient protein production in various in vitro and in vivo translation systems.

Synthetic biology, an interdisciplinary field at the intersection of engineering and biology, has garnered considerable attention for its potential applications in plant science. By exploiting engineering principles, synthetic biology enables the redesign and construction of biological systems to manipulate plant traits, metabolic pathways, and responses to environmental stressors. This review explores the evolution and current state of synthetic biology in plants, highlighting key achievements and emerging trends. Synthetic biology offers innovative solutions to longstanding challenges in agriculture and biotechnology for improvement of nutrition and photosynthetic efficiency, useful secondary metabolite production, engineering biosensors, and conferring stress tolerance. Recent advances, such as genome editing technologies, have facilitated precise manipulation of plant genomes, creating new possibilities for crop improvement and sustainable agriculture. Despite its transformative potential, ethical and biosafety considerations underscore the need for responsible deployment of synthetic biology tools in plant research and development. This review provides insights into the burgeoning field of plant synthetic biology, offering a glimpse into its future implications for food security, environmental sustainability, and human health.

Cell division is important for organisms to grow and repair damaged tissues. A mutant screen in rice has identified dwarf korpokkur (kor) mutants that code for a novel protein potentially involved in mitosis including cytokinesis in rice. The KOR gene is expressed during the mitotic phase and a defect in the KOR gene induces cells with two nuclei. Analysis of kor mutants suggests that the KOR gene promotes cell division in the rice leaf primordia for a period after initiation, and maintains proper cell morphology especially in non-meristematic tissues. Additionally, kor mutants showed a delayed transition from juvenile phase to adult phase. Future research will shed light on the relationship between the mitotic defect and other features observed in the kor mutants.

To further enhance our understanding of stomatal regulation, we investigated the novel transcription factors involved in this process. Our findings reveal that SHOOT GRAVITROPISM 5 (SGR5) is involved in the stomatal response to darkness in Arabidopsis. Water loss measurements showed that SGR5-overexpressing plants retained more water, whereas SGR5-knockout lines exhibited increased water loss compared with the control. Unexpectedly, our analyses indicated that SGR5 was not associated with the abscisic acid signaling pathway, in contrast to its homologous transcription factor, INDETERMINATE DOMAIN 14. Instead, SGR5-knockout lines exhibited weakened stomatal closure responses upon transition to darkness. Collectively, our results highlight the regulatory role of SGR5 in mediating stomatal movement in response to darkness.