Breeding Targets to Improve Biomass Quality in Miscanthus

Abstract

Lignocellulosic crops are attractive bioresources for energy and chemicals production within a sustainable, carbon circular society. Miscanthus is one of the perennial grasses that exhibits great potential as a dedicated feedstock for conversion to biobased products in integrated biorefineries. The current biorefinery strategies are primarily focused on polysaccharide valorization and require severe pretreatments to overcome the lignin barrier. The need for such pretreatments represents an economic burden and impacts the overall sustainability of the biorefinery. Hence, increasing its efficiency has been a topic of great interest. Inversely, though pretreatment will remain an essential step, there is room to reduce its severity by optimizing the biomass composition rendering it more exploitable. Extensive studies have examined the miscanthus cell wall structures in great detail, and pinpointed those components that affect biomass digestibility under various pretreatments. Although lignin content has been identified as the most important factor limiting cell wall deconstruction, the effect of polysaccharides and interaction between the different constituents play an important role as well. The natural variation that is available within different miscanthus species and increased understanding of biosynthetic cell wall pathways have specified the potential to create novel accessions with improved digestibility through breeding or genetic modification. This review discusses the contribution of the main cell wall components on biomass degradation in relation to hydrothermal, dilute acid and alkaline pretreatments. Furthermore, traits worth advancing through breeding will be discussed in light of past, present and future breeding efforts.

Detection and Analysis of Syntenic Quantitative Trait Loci Controlling Cell Wall Quality in Angiosperms

“…Examples of these crops include miscanthus, switchgrass, poplar or willow, which share a sequenced genome; but also herbaceous and woody biomass species for which genetic resources are even more scarce, as giant reed, reed canary grass, black locust, and siberian elm ( Pancaldi and Trindade, 2020 ). These crops should therefore be improved, and a preeminent target trait is certainly cell wall quality, which is the major determinant of biomass quality for bio-based applications ( Van Der Weijde et al, 2013 ; Isikgor and Becer, 2015 ; Van Der Cruijsen et al, 2021 ). Specifically, the total content of the major cell wall components – cellulose, hemicelluloses, and lignin – as well as cellulose cristallinity, degree and type of hemicellulose substitutions, and the monolignol composition of the lignin polymers are all target characters at the basis of biomass quality ( Van Der Weijde et al, 2013 ; Van Der Cruijsen et al, 2021 ).…”

“…These crops should therefore be improved, and a preeminent target trait is certainly cell wall quality, which is the major determinant of biomass quality for bio-based applications ( Van Der Weijde et al, 2013 ; Isikgor and Becer, 2015 ; Van Der Cruijsen et al, 2021 ). Specifically, the total content of the major cell wall components – cellulose, hemicelluloses, and lignin – as well as cellulose cristallinity, degree and type of hemicellulose substitutions, and the monolignol composition of the lignin polymers are all target characters at the basis of biomass quality ( Van Der Weijde et al, 2013 ; Van Der Cruijsen et al, 2021 ). Applying translational genomics to the improvement of these traits in orphan biomass crops is expected to significantly speed up the development of varieties that combine resilience to marginal land conditions with production of large and good-quality biomass yields ( Pancaldi and Trindade, 2020 ).…”

Moisture content estimation and senescence phenotyping of novel Miscanthus hybrids combining UAV‐based remote sensing and machine learning

“…Miscanthus is a promising perennial crop that can achieve high biomass production on marginal lands (Amaducci et al, 2016;van der Cruijsen et al, 2021;Pancaldi & Trindade, 2020;Shepherd et al, 2020). Due to its perennial nature, Miscanthus has a limited input requirement and is cultivated under no tillage regime leading to multiple ecosystem services provision (Agostini et al, 2021;Ferrarini et al, 2016Ferrarini et al, , 2021Martani et al, 2021).…”

UAV Remote Sensing for High-Throughput Phenotyping and for Yield Prediction of Miscanthus by Machine Learning Techniques

“…Yield is one of the most important traits of Miscanthus [1] and has been the primary focus of the research portfolio on Miscanthus in the last ten years [2][3][4]. Independent and collaborative efforts to breed high-yielding Miscanthus hybrids to produce sustainable biomass for the growing bio-based European market are ongoing in several countries [5][6][7]. In the EU-BBI demo-project GRACE, novel and highly upscalable seed-based Miscanthus hybrids are evaluated [5,[7][8][9][10] in seven European countries.…”

“…Independent and collaborative efforts to breed high-yielding Miscanthus hybrids to produce sustainable biomass for the growing bio-based European market are ongoing in several countries [5][6][7]. In the EU-BBI demo-project GRACE, novel and highly upscalable seed-based Miscanthus hybrids are evaluated [5,[7][8][9][10] in seven European countries. Most yield prediction to date has relied on crop growth models driven by climate and soil data with crop specific parameters [11][12][13].…”