Sensitive detection of genetically modified maize based on a CRISPR/Cas12a system.

With the vigorous development of biotechnology, genetically modified organisms (GMOs) have become more and more common. In order to effectively supervise and administrate them, the rapid and accurate detection of GMOs is urgently demanded. Here, GMO gene-specific sensing methods based on colorimetry and surface-enhanced Raman scattering (SERS) were proposed based on the lateral branch cleavage function of the CRISPR/Cas12a system. Two transgenes, pCaMV35S and M810 Cry1Ab, were chosen as targets for transgenic crops. By using these methods, we performed transgenic detection on five types of maize leaves and successfully distinguished transgenic from non-transgenic samples. The colorimetric method is rapid, economical and available for field detection. The SERS approach, giving a higher sensitivity to 100 fM, is more suitable for laboratory application scenarios. This study explores practical transgenic detection approaches and will be valuable for the supervision of GMOs.

Gene editing of ZmGA20ox3 improves plant architecture and drought tolerance in maize.

KEY MESSAGE: Editing ZmGA20ox3 can achieve the effect similar to applying Cycocel, which can reduce maize plant height and enhance stress resistance. Drought stress, a major plant abiotic stress, is capable of suppressing crop yield performance severely. However, the trade-off between crop drought tolerance and yield performance turns out to be significantly challenging in drought-resistant crop breeding. Several phytohormones [e.g., gibberellin (GA)] have been reported to play a certain role in plant drought response, which also take on critical significance in plant growth and development. In this study, the loss-of-function mutations of GA biosynthesis enzyme ZmGA20ox3 were produced using the CRISPR-Cas9 system in maize. As indicated by the result of 2-year field trials, the above-mentioned mutants displayed semi-dwarfing phenotype with the decrease of GA1, and almost no yield loss was generated compared with wild-type (WT) plants. Interestingly, as revealed by the transcriptome analysis, differential expressed genes (DEGs) were notably enriched in abiotic stress progresses, and biochemical tests indicated the significantly increased ABA, JA, and DIMBOA levels in mutants, suggesting that ZmGA20ox3 may take on vital significance in stress response in maize. The in-depth analysis suggested that the loss function of ZmGA20ox3 can enhance drought tolerance in maize seedling, reduce Anthesis-Silking Interval (ASI) delay while decreasing the yield loss significantly in the field under drought conditions. The results of this study supported that regulating ZmGA20ox3 can improve plant height while enhancing drought resistance in maize, thus serving as a novel method for drought-resistant genetic improvement in maize.

TMEM216 promotes primary ciliogenesis and Hedgehog signaling through the SUFU-GLI2/GLI3 axis.

Primary cilia are enriched in signaling receptors, and defects in their formation or function can induce conditions such as polycystic kidney disease, postaxial hexadactyly, and microphthalmia. Mammalian Hedgehog (Hh) signaling is important in the development of primary cilia, and TMEM216, a transmembrane protein that localizes to the base of cilia, is also implicated in ciliogenesis in zebrafish. Here, we found that Tmem216-deficient mice had impaired Hh signaling and displayed typical ciliopathic phenotypes. These phenomena were also observed in cells deficient in TMEM216. Furthermore, TMEM216 interacted with core Hh signaling proteins, including SUFU, a negative regulator of Hh, and GLI2/GLI3, transcription factors downstream of Hh. The competition between TMEM216 and SUFU for binding to GLI2/GLI3 inhibited the cleavage of GLI2/GLI3 into their repressor forms, which resulted in the nuclear accumulation of full-length GLI2 and the decreased nuclear localization of cleaved GLI3, ultimately leading to the activation of Hh signaling. Together, these data suggest that the TMEM216-SUFU-GLI2/GLI3 axis plays a role in TMEM216 deficiency-induced ciliopathies and Hh signaling abnormalities.