# A phenomics-based dynamic model of growth and yield to simulate hundreds of maize hybrids in the diversity of European environments

Sébastien Lacube, Boris Parent, Francois Tardieu

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Sébastien Lacube, Boris Parent, Francois Tardieu. A phenomics-based dynamic model of growth and yield to simulate hundreds of maize hybrids in the diversity of European environments. 60. Maize Genetics Conference, Mar 2018, Saint-Malo, France. 2018. [hal-02733739](https://hal.inrae.fr/hal-02733739)

HAL Id: hal-02733739

https://hal.inrae.fr/hal-02733739

Submitted on 2 Jun 2020

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Distributed under a Creative Commons Attribution 4.0 International License
ZmbZIP22 is a new transcription factor for 27-kD γ-zein gene
(submitted by Chaobin Li <chaobinli@cau.edu.cn>)

Full Author List: Li, Chaobin<fnref n="1" />; Yue, Yihong<fnref n="2" />; Ling, Huiling<fnref n="2" />; Xing, Yingying<fnref n="2" />; Zhu, Tongdan<fnref n="2" />; Song, Rentao<fnref n="1" />,<fnref n="2" />

Zeins are the most abundant storage proteins in maize kernel, affecting maize nutrient quality and kernel hardness. The 27-kD γ-zein is a highly expressed zein that plays crucial role for zein protein body formation. So far, several transcription factors (TFs) (O2, PBF1 and OHPs) have been identified for the 27-kD γ-zein gene transcription. However the complexity of 27-kD γ-zein transcription regulation is not fully revealed. In this study, a new factor binds to the 27-kD γ-zein gene promoter was identified through probe affinity purification and mass spectrometry analysis. This new factor belongs to bZIP type TF (hence named as ZmbZIP22) and is endosperm specifically expressed. ZmbZIP22 can directly bind the ACAGCTCA box in 27-kD γ-zein promoter, and trans-activates the promoter in tobacco cells. The bZIP22 mutants were generated by CRISPR/Cas9, and the 27-kD γ-zein gene expression was significantly decreased in mutant kernels. ChIP-seq analysis confirmed that ZmbZIP22 binds the 27-kD γ-zein gene promoter in vivo, and also identified additional direct targets of ZmbZIP22. Moreover, ZmbZIP22 can interact with other TFs of 27-kD γ-zein gene, such as PBF1, OHP1 and OHP2, but not with O2. Transactivation assay with combinations of these TFs revealed different interaction mode to the transcription activity of 27-kD γ-zein promoter. These results suggested that ZmbZIP22 is a functional TF for 27-kD γ-zein gene, and it coordinates the regulation of 27-kD γ-zein promoter with other known TFs.

Funding acknowledgement: National Natural Science Foundation of China (NSFC)

A phenomics-based dynamic model of growth and yield to simulate hundreds of
maize hybrids in the diversity of European environments
(submitted by Francois Tardieu <francois.tardieu@inra.fr>)

Full Author List: Lacube, Sebastien<fnref n="1" />; Parent, Boris<fnref n="1" />; Tardieu, Francois<fnref n="1" />

Under soil water deficit, plants limit transpiration by decreasing leaf area to save water for the end of the crop cycle. A large genetic diversity is observed in maize for the processes involved in this response. We aimed to predict which combination of trait values related to leaf growth would be beneficial in the diversity of European environments. For this purpose, we have first analysed the genetic and environmental controls of leaf elongation and widening. A series of experiments revealed that leaf elongation is related to plant water status whereas leaf widening is related to the carbon available to plant. A GWAS analysis also revealed that elongation and widening depend on different alleles. This analysis resulted in a model that allows simulating leaf area in a large variety of environmental scenarios. This model resulted in estimated leaf area and yield that were close to those observed in 15 fields over Europe. The model was then used to determine ideotypes of leaf growth adapted to the different environmental scenarios. Results indicate that sensitive hybrids perform better in southern Europe under rainfed conditions while less-sensitive genotypes perform better in northern Europe or in irrigated fields. However, the best combinations of parameters determined in an unconstrained phenotypic space were not available in the observed genetic diversity. Overall, this study provides elements on where and when a combination of trait values can give a comparative advantage on yield, together with the boundary of possibilities within the current genetic diversity.

Funding acknowledgement: INRA, ANR

<footnote n="1">¹ National Maize Improvement Center of China, China Agricultural University, Beijing 100193, China</footnote>

<footnote n="2">² Shanghai Key Laboratory of Bio-Energy Crops, Plant Science Center, School of Life Sciences, Shanghai University, Shanghai 200444, China</footnote>

<footnote n="1">¹ INRA LEPSE Montpellier France F34000</footnote>