Recently, a collaborative research of Maize Functional Genomics Innovation Team and Crop Metabolic Regulation and Biofortification Innovation Team of Biotechnology Research Institute, Chinese Academy of Agricultural Sciences (BRI-CAAS) constructed the first spatiotemporally transcrioptional network and uncovered the new mechanism that regulate maize stalk elongation and growth, which provides a new insight and supplies excellent gene sources for maize improvement. Thisresearch has been published in Plant Biotechnology Journal with the title “A spatiotemporal transcriptomic network dynamically modulates stalk development in maize”.
The stalk elongation occurs mainly before the shoot apical meristem initiates to produce reproductive tissues in response to developmental and environmental signals. Many important biological processes may involve in stalk elongation, including cell division, cell wall synthesis, and vascular bundle formation. Considering that maize plant height primarily results from stalk elongation driven by cell division and cell expansion within the internodes, identifying new regulators that directly regulate cell elongation may be a solution to explore ideal plant architecture. Although several transcriptional profiling of the specific internodes have been conducted, little is known about the transcriptional dynamics and the regulatory network in the whole maize stalks at the fast elongation and maturation stages.
In this work, the scientists obtained 58 transcriptomes of individual internodes of the maize stalks from elongation to maturation stage to elucidate the spatial-temporal gradient of culm development. This high-density, time-course transcriptome analysis clearly highlighted four distinct zones at elongated and maturation stalks. 13,964 genes with a high coefficient of variation were classed into nine co-expression modules according to their expression patterns, which provided further insight into the spatial-temporal transitions in mRNA abundance of the four zones. The phenotype-specific network modules were identified by combining transcriptome data with stalk phenotypes with a weighted gene co-expression network analysis (WGCNA). A number of crucial genes involved in division, elongation and maintenance, such as cell elongation regulatory genes ZmD1 (cytochrome P450 D1,CYP90D1) and ZmBZR1 (Brassinzole-resistant 1), are identified as hub genes in the elongated stalk network. The dynamic transcriptome also implied many hormone-related and transcription factors genes essential for stalk elongation and growth in maize. Moreover, the scientist validated one newly identified gene, ZmD1, which mutant exhibits shorter stature and bulkier culm than the wild type (WT), corroborating the critical role of ZmD1 gene in maize stalk development. Therefore, this study provide insights into the genetic architecture of maize stalk elongation and developing new varieties with ideal stalk lengths and width, being useful for molecular breeding and genetic improvements.
Dr. Le Liang (assistant professor), Weijun Guo (PhD student), Danyao Du (Master) and Xiaoyuan Zhang (PhD) are the co-first authors. Dr.Li Pu (Professor) and Dr. Chunyi Zhang are the co-corresponding authors. This work was supported by the National Key Research and Development Program of China (2021YFF1000300), the International Science & Technology Innovation Program of Chinese Academy of Agricultural Sciences (CAASTIP, Y2020YJ09), Fundamental Research Funds for Central Non-Profit of Chinese Academy of Agricultural Sciences (CAAS-ZDRW202109), the Innovation Program of Chinese Academy of Agricultural Sciences (CAAS-ZDRW202004), the 2020 Research Program of Sanya Yazhou Bay Science and Technology City (SKJC-2020-02-005).
More details can be found at the link:
https://doi.org/10.1111/pbi.13909
Fiugre. Transcriptomic analyses of internodes of the maize stalk at the elongation and maturation stages |