bioRxiv Science⌕ Search

bioRxiv · 10.1101/201665

Leaf rolling in maize crops: from leaf scoring to canopy level measurements for phenotyping

Abstract

Leaf rolling in maize crops is one of the main plant reactions to water stress that may be visually scored in the field. However, the leaf scoring did not reach the high-throughput desired by breeders for efficient phenotyping. This study investigates the relationship between leaf rolling score and the induced canopy structure changes that may be accessed by high-throughput remote sensing techniques.\n\nResults gathered over a field phenotyping platform run in 2015 and 2016 show that leaf starts to roll for the water stressed conditions around 9:00 and reaches its maximum around 15:00. Conversely, genotypes conducted under well watered conditions do not show any significant rolling during the same day. Leaf level rolling was very strongly correlated to canopy structure changes as described by the fraction of intercepted radiation fIPARWS derived from digital hemispherical photography. The changes in fIPARWS were stronly correlated (R2=0.86, n=50) to the leaf level rolling visual score. Further, a very good consistency of the genotype ranking of the fIPARWS changes during the day was found ({rho}=0.62). This study demonstrating the strong coordination between leaf level rolling and its impact on canopy structure changes poses the basis for new high-throughput remote sensing methods to quantify this water stress trait.\n\nHighlighThe diurnal dynamics of leaf rolling scored visually is strongly related to canopy structure changes that can be documented using Digital hemispherical photography. Consequences for high-throughput field phenotyping are discussed

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Baret, F., Madec, S., Irfan, K., Lopez, J., Comar, A., Hemmerle, M., Dutartre-Cohen, D., Praud, S., Tixier, M.-H.. 2017-10-11. Leaf rolling in maize crops: from leaf scoring to canopy level measurements for phenotyping. https://doi.org/10.1101/201665

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Photosynthesis-derived carbohydrate supply sustains CuCl2-induced phytoalexin production in rice leaves

Phytoalexins are antimicrobial metabolites whose biosynthesis is triggered by signaling activated by both biotic and abiotic elicitors, but the physiological conditions that sustain their production remain poorly understood. Here, we examined how light and carbohydrate availability affect CuCl2-induced production of diterpenoid (phytocassanes and momilactones) and flavonoid (sakuranetin) phytoalexins in rice (Oryza sativa L.) leaf disks. Darkness strongly suppressed both the accumulation of all three phytoalexin groups and the induction of their biosynthetic genes. In darkness, endogenous sucrose, glucose, and fructose declined to 3%-8% of the levels in the light, whereas early accumulation of jasmonic acid and jasmonoyl-L-isoleucine (JA-Ile) was not detectably reduced. Exogenous sucrose restored phytoalexin accumulation in darkness in a dose-dependent manner, together with the expression of the suppressed biosynthetic genes, whereas equimolar mannitol had no effect. Glucose also restored sakuranetin accumulation in darkness but only partially restored diterpenoid accumulation, whereas the glucose analog 2-deoxy-D-glucose did not, and it suppressed CuCl2-induced accumulation in the light in a dose-dependent manner. In the light, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosynthetic electron transport, depleted soluble sugars and suppressed phytoalexin accumulation, and sucrose reversed this suppression. Sugars alone induced little phytoalexin accumulation, indicating that carbohydrates act permissively rather than as elicitors. Diterpenoid phytoalexins depended more strongly on light than sakuranetin, yet both classes depended on carbohydrate availability. These results indicate that photosynthesis-derived carbohydrate supply sustains elicitor-induced phytoalexin production in rice leaves and largely accounts for its light dependence.

plant biology↗

Transcriptome analysis provides insights into candidate genetic regulators of birch response to salt stress

Abstract Background: Soil salinization is a worldwide matter of concern and can result in a series of agricultural and ecological problems. Previous transcriptome data have shown genetic regulatory mechanisms of salt stress response in a salt-tolerant species of Betula halophila and a salt-sensitive species of B. platyphylla, but comparative analysis of transcriptional changes in the the two species remains limited. Aims: We compared gene expression in leaves of B. halophila and leaves and roots of B. platyphylla. Methods: Differentially expressed genes (DEGs) were identified after 24 h of salt stress, followed by Gene Ontology enrichment and gene regulatory network (GRN) construction. Selected DEGs were examined by quantitative real-time PCR (RT-qPCR). Results: Compared with 0 h, 956 DEGs were found in B. halophila leaves (BHLeaf), 2,955 in B. platyphylla leaves (BPLeaf), and 3,827 in B. platyphylla roots (BPRoot). BHLeaf DEG expression patterns were similar to those of BPRoot. DEGs from BHLeaf and BPRoot were enriched in cell wall organization or biogenesis, whereas hormone biosynthesis and signaling genes were altered mainly in B. platyphylla. RT-qPCR showed that selected DEGs were induced by 200 mM NaCl for 24 h in B. platyphylla. Conclusions: Our work uncovered genetic mechanisms of salt stress response commonly and uniquely occurring in two birch species and provides resources for breeding salt-tolerant birch.

plant biology↗

Minimal requirements and evolution of polar membrane targeting in the land plant SOSEKI protein family

Accurate spatial distribution of polar proteins is essential for cell function, but mechanisms underlying polar protein targeting in plants are poorly understood. Here, we dissect the molecular mechanisms underlying the polar targeting of the SOSEKI1 (SOK1) protein in Arabidopsis thaliana. Using extensive mutagenesis and truncation analyses of the polarity domain, we mapped the minimal polarity fragment necessary and sufficient for stable polar targeting to a 25-amino-acid region. This region likely forms an amphipathic helix, and mutations reveal that both its polar and apolar faces are essential for membrane association and polarity. Using phylogenetic analysis, we reconstruct the evolutionary history of the minimal polar targeting region across land plants. Using cross-species expression and protein localization, we infer the ancestral polar SOK localization pattern and show how it remained remarkably conserved, only to diversify upon gene duplication. This work identifies a polar targeting peptide in plants, reveals a mechanism for polar membrane targeting of a plant protein family, and demonstrates both conservation and diversification within this family.

plant biology↗