Application of genetic varietal identification of different rice varieties.
The Italian law requires a registry documenting the morphological characters of individual rice varieties. The visual recognition analysis on milled rice does not always allow to morphologically discriminate the traditional varieties belonging to the same group among themselves or with respect to the respective traditional variety.
To overcome these difficulties, a recent study carried out by a group of Italian researchers (Trivero et al., 2024) proposed a method of genetic varietal identification based on SNP molecular markers (Single Nucleotide Polymorphism). In particular, the aim of the study was to allow for the genetic discrimination of 30 rice varieties: 6 classic, 23 traditional and 1 belonging to the “round” group. The tests were carried out through the following steps: Defect analysis and grinding, DNA extraction, sample library preparation, DNA sequencing, and bioinformatics analysis of data.
This procedure made it possible to compare the genetic information of the 30 varieties with the reference genome of rice (Nipponbare) and thus obtain a panel of 301 SNPs capable of discriminating all the 30 varieties investigated, making it possible to establish a genetic database. The same 30 varieties were analysed again, and the results confirmed the discriminatory power of the chosen SNPs. However, further analysis is necessary to expand the database by introducing the “round” group, as well as to identify the individual varieties present in mixtures and their relative percentage abundance, thus adding to the qualitative character of the analysis also the quantitative one.
Assessment of mobility and uptake of inorganic contaminants in rice.
Rice is traditionally grown under submerged soil conditions. This, however, causes profound differences in the biogeochemical dynamics of the nutritional and contaminating elements in the rice paddies and, therefore, their availability for rice. In particular, arsenic (As) and cadmium (Cd) can reach high concentrations in the grain. Therefore, the aim of a recent study, carried out by a group of Italian researchers (Martin et al., 2024), was to analyse the mechanisms that regulate the mobility and uptake of inorganic contaminants in rice.
The results show that the most important variable in regulating the uptake of arsenic by the cereal is irrigation water management: Rice absorbs most of the arsenic during the rising phase and planned dry periods – even short ones – are effective in significantly reducing the concentration of arsenic in the plant and the grain compared to the control maintained in continuous submersion. Cadmium is absorbed mainly in the final stages of the cultivation cycle, starting from flowering.
As it becomes more mobile under aerobic conditions, it is important to keep the plant under flooded paddy conditions as long as possible after flowering, possibly until the wax-ripe stage so as to avoid a significant increase of the element in the rice grain. Finally, further insights are necessary to clarify the still unknown dynamics of nickel in rice paddies, depending on the different physico-chemical characteristics of the soil and the agronomic techniques adopted, and the mechanisms of absorption and translocation by the rice plant, in order to identify possible strategies to reduce the concentration of this contaminant as well.
References: Trivero et al., Proceedings of the 13th AISTEC CONFERENCE, Turin, June 19-21, 2024, 152-154; Martin et al., Proceedings of the 13th AISTEC CONFERENCE, Turin, June 19-21, 2024, 52-56.
