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Background: Photoperiodism refers to the ability of plants to measure day length to determine the season. This ability enables plants to coordinate internal biological activities with external changes to ensure normal growth. However, the influence of the photoperiod on maize flowering and stress responses under long-day (LD) conditions has not been analyzed by comparative transcriptome sequencing. The ZmCCT gene was previously identified as a homolog of the rice photoperiod response regulator Ghd7, and associated with the major quantitative trait locus (QTL) responsible for Gibberella stalk rot resistance in maize. However, its regulatory mechanism has not been characterized. Results: We mapped the ZmCCT-associated QTL (ZmCCT-AQ), which is approximately 130 kb long and regulates photoperiod responses and resistance to Gibberella stalk rot and drought in maize. To investigate the effects of ZmCCT-AQ under LD conditions, the transcriptomes of the photoperiod-insensitive inbred line Huangzao4 (HZ4) and its near-isogenic line (HZ4-NIL) containing ZmCCT-AQ were sequenced. A set of genes identified by RNA-seq exhibited higher basal expression levels in HZ4-NIL than in HZ4. These genes were associated with responses to circadian rhythm changes and biotic and abiotic stresses. The differentially expressed genes in the introgressed regions of HZ4-NIL conferred higher drought and heat tolerance, and stronger disease resistance relative to HZ4. Co-expression analysis and the diurnal expression rhythms of genes related to stress responses suggested that ZmCCT and one of the circadian clock core genes, ZmCCA1, are important nodes linking the photoperiod to stress tolerance responses under LD conditions. Conclusion: Our study revealed that the photoperiod influences flowering and stress responses under LD conditions. Additionally, ZmCCT and ZmCCA1 are important functional links between the circadian clock and stress tolerance. The establishment of this particular molecular link has uncovered a new relationship between plant photoperiodism and stress responses. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) extrusion-based bioprinting is the most widely used bioprinting technology to fabricate bionic tissue or organ constructs by combining biomaterial ink and living cells for tissue engineering and regenerative medicine. One critical issue of this technique is the selection of suitable biomaterial ink to simulate extracellular matrix (ECM) that provides mechanical support for cells and regulates their physiological activities. Previous studies have demonstrated that it is an enormous challenge to form and maintain reproducible 3D constructs and eventually achieve the balance among biocompatibility, mechanical properties, and printability. This review highlights the properties of extrusion-based biomaterial inks and recent developments as well as details various biomaterial inks classified by their function. Key approaches related to their modification methods according to the functional requirements are also discussed, along with the selection strategies by varying extrusion paths and methods in extrusion-based bioprinting. This systematical review will assist researchers in identifying the most suitable extrusion-based biomaterial inks based on their requirements, as well as in elaborating current challenges and prospects of extrudable biomaterial inks in the field of bioprinting of in vitro tissue models., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright: © 2023 Li X, Zheng F, Wang X, et al.)