An article published in the journal “Nature” reports the results of a high-quality sequencing of sugarcane (photo plant Ton Rulkens) DNA. The name generally refers to the Saccharum officinarum species but actually, the cultivars are hybrids with the Saccharum spontaneum species, sometimes called wild sugarcane. The polyploid sugarcane genome has become one of the most complex known, which is why it’s been so difficult to completely sequence. Now a team of researchers combined different genetic techniques to obtain the genome of the variety referred to as R570, a typically modern cultivar.
The history of sugarcane is long and complex, as it’s believed that its domestication began about 10,000 years ago in New Guinea with the Saccharum officinarum species, which is believed to be derived from the Saccharum robustum species. Only after millennia did its slow diffusion around the world begin and about a century ago, hybridization occurred with the Saccharum spontaneum species which gave rise to today’s cultivars. Some cultivars are considered separate species such as Saccharum barberi and Saccharum sinense.
The complexity of sugarcane DNA is also due to its polyploidism, which means it contains more copies of its chromosomes than the typical plant. An article published in 2017 in the journal “Genome Biology and Evolution” suggests that genome duplication occurred independently in the two species that produced the current hybrids.
The R570 cultivar was created only in 1980 but in previous decades, other hybrids were produced with the aim of obtaining cultivars adapted to stressful environmental conditions and resistant to diseases. The basic idea of the hybridization was to combine the productivity of the Saccharum officinarum species with the disease resistance of the Saccharum spontaneum species. Cultivars are also used as feedstock and for the production of biofuels and other bioproducts, further reasons to have all the information that can help improve the different cultivars.
Various partial sequencing of sugarcane cultivars were conducted in past years and this new result will offer new possibilities for improvement. Today a lot of sugar is produced from the sugar beet but the cultivation of sugarcane remains very important in various areas of the world. In recent years, it seems that it has become impossible to increase the yield of these crops and at least part of the problem may lie in their limited genetic diversity.
Knowing the complete genetic characteristics of sugarcane is important but some of them are the expression of genes that weren’t sequenced in previous genetic studies. Now a reference genome was created by combining various genetic sequencing techniques that include a new method.
These findings will also help compare sugarcane genes with those of other commonly cultivated plants that are the subject of genetic studies. This will help understand the influence of certain genes that control traits that increase crop yield, with a growing attention to the sustainability of those crops, and the genes that contribute to disease resistance. In essence, these in-depth genetic studies directly concern a plant but can also influence the cultivation of other plants.
