Isolation of structurally distinct lignin–carbohydrate fractions from maize stem by sequential alkaline extractions and endoglucanase treatment

Sequential fractionation of extractive-free maize stems was carried out using two mild alkaline extractions (0.5 and 2 M NaOH, 20 'C, 24 h) before and after endoglucanase treatment. This procedure provided two lignin–carbohydrate fractions (LC1 and LC2) recovered after each alkali treatment. LC1 and LC2 contained 39% and 8% of the total lignin amount, respectively. These two fractions contained structurally distinct lignin molecules. While the content of resistant interunit bonds in lignin was 77% in LC1, it was increased up to 98% in LC2. Not unexpectedly, both alkali-soluble fractions contained substantial amount of p-coumaric and ferulic acids ether-linked to lignins. These results outline heterogeneity of maize stem lignins related to fractionation of grass materials

Water Deficit-Responsive QTLs for Cell Wall Degradability and Composition in Maize at Silage Stage

The use of lignocellulosic biomass for animal feed or biorefinery requires the optimization of its degradability. Moreover, biomass crops need to be better adapted to the changing climate and in particular to periods of drought. Although the negative impact of water deficit on biomass yield has often been mentioned, its impact on biomass quality has only been recently reported in a few species. In the present study, we combined the mapping power of a maize recombinant inbred line population with robust near infrared spectroscopy predictive equations to track the response to water deficit of traits associated with biomass quality. The population was cultivated under two contrasted water regimes over 3 consecutive years in the south of France and harvested at silage stage. We showed that cell wall degradability and β-O-4-linked H lignin subunits were increased in response to water deficit, while lignin and p-coumaric acid contents were reduced. A mixed linear model was fitted to map quantitative trait loci (QTLs) for agronomical and cell wall-related traits. These QTLs were categorized as “constitutive” (QTL with an effect whatever the irrigation condition) or “responsive” (QTL involved in the response to water deficit) QTLs. Fifteen clusters of QTLs encompassed more than two third of the 213 constitutive QTLs and 13 clusters encompassed more than 60% of the 149 responsive QTLs. Interestingly, we showed that only half of the responsive QTLs co-localized with constitutive and yield QTLs, suggesting that specific genetic factors support biomass quality response to water deficit. Overall, our results demonstrate that water deficit favors cell wall degradability and that breeding of varieties that reconcile improved drought-tolerance and biomass degradability is possible

Etude de facteurs biochimiques et génétiques explicatifs de la variabilité pour la valeur alimentaire du maïs fourrage

*INRA, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan (FRA) Diffusion du document : INRA, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan (FRA) Diplôme : Dr. Ing

Etude de facteurs biochimiques et génétiques explicatifs de la variabilité pour la valeur alimentaire du maïs fourrage

*INRA, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan (FRA) Diffusion du document : INRA, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan (FRA) Diplôme : Dr. Ing

In vivo digestibility and biomass yield in normal and BM3 hybrids, made from crossing early and medium late lines of maize.

International audienc

Inbred line evaluation and breeding for digestibility-related traits in forage maize

International audienc

Bioconversion de résidus agricoles en lipides avec la bactérie <em>Streptomyces lividans</em>

Article page 17 dans le rapport d'activité du département CEPIA : O'Donohue, M., DELCLOS, M., Prevosto, L., Département CEPIA (2017). Recherches et Innovations pour l'Aliment et les Bioproduits. 44 p., DOI : 10.15454/1.508483782951509E12 - https://prodinra.inra.fr/record/41031

Histological quantification of maize stem sections from FASGA-stained images

Background: Crop species are of increasing interest both for cattle feeding and for bioethanol production. The degradability of the plant material largely depends on the lignification of the tissues, but it also depends on histological features such as the cellular morphology or the relative amount of each tissue fraction. There is therefore a need for high-throughput phenotyping systems that quantify the histology of plant sections. Results: We developed custom image processing and an analysis procedure for quantifying the histology of maize stem sections coloured with FASGA staining and digitalised with whole microscopy slide scanners. The procedure results in an automated segmentation of the input images into distinct tissue regions. The size and the fraction area of each tissue region can be quantified, as well as the average coloration within each region. The measured features can discriminate contrasted genotypes and identify changes in histology induced by environmental factors such as water deficit. Conclusions: The simplicity and the availability of the software will facilitate the elucidation of the relationships between the chemical composition of the tissues and changes in plant histology. The tool is expected to be useful for the study of large genetic populations, and to better understand the impact of environmental factors on plant histology