Genetic Improvement of Arundo donax L.: Opportunities and Challenges

Abstract

Arundo donax L., the giant reed—being a long-duration, low-cost, non-food energy crop able to grow in marginal lands—has emerged as a potential alternative to produce biomass for both energy production, with low carbon emissions, and industrial bioproducts. In recent years, pioneering efforts have been made to genetically improve this very promising energy crop. This review analyses the recent advances and challenges encountered in using clonal selection, mutagenesis/somaclonal variation and transgenesis/genome editing. Attempts to improve crop yield, in vitro propagation efficiency, salt and heavy metal tolerance by clonal selection were carried out, although limited by the species’ low genetic diversity and availability of mutants. Mutagenesis and somaclonal variation have also been attempted on this species; however, since Arundo donax is polyploid, it is very difficult to induce and select promising mutations. In more recent years, genomics and transcriptomics data are becoming available in Arundo, closing the gap to make possible the genetic manipulation of this energy crop in the near future. The challenge will regard the functional characterization of the genes/sequences generated by genomic sequencing and transcriptomic analysis in a complex polyploid genome.

Arundo donax L. growth potential under different abiotic stress

“…Danelli et al [ 98 ] summarize in four steps the objectives of the genetic improvement of giant reed in the short and medium term: i) plant production (best clones), ii) stand establishment (freeze and herbicide tolerance), iii) crop growth (stress resistance, phytoremediation capacity) and biomass processing (lower lignin content). Studies suggest that clonal selection is the major form of selection for good yield, as well as in vitro production and stress exposure experiments, since giant reed being a polyploid species can be difficult to genetically modify.…”

“…In the current context where the bioeconomy and the green economy have as their main objective the production of biomaterials, energy derived from biomass and renewable energy sources alternative to fossil fuels, giant reed is a relevant option, both for its decontaminating power and its tolerance to various abiotic factors [ 104 ]. Therefore, the giant reed can be used for bioremediation and ecosystem services [ 58 ], while taking advantage of the biomass for energy production, closing a sustainable economy cycle following the circular economy approach [ 66 , 82 , 98 ].…”

Arundo donax L. Biomass Production in a Polluted Area: Effects of Two Harvest Timings on Heavy Metals Uptake

“…Alamo; and as control, the mixed meadows (MM) species already present in the area. The A. donax L. clone Ad20 represents a promising genotype for large scale cultivation, due to its production potential and efficient propagation [31][32][33]. The control MM was constituted by the predominant species Medicago sativa and Chenopodium album.…”

Alkaline Salt Tolerance of the Biomass Plant Arundo donax

“…It is native to dunes, wetlands, and riparian habitats and as a rhizomatous C3 grass, its root system can reach more than 5 m depth. The annual-biennial stems grow to 8-10 m in height and 3-4 cm in diameter [24]. It is characterized by an unusually high photosynthetic potential and a relatively high transpiration rate [25,26].…”