Domesticated rice Oryza sativa L. is a major staple food worldwide, and the cereal most sensitive to salinity. It originated from the wild ancestor Oryza rufipogon Griff., which was reported to possess superior salinity tolerance. Here, we examined the morpho-physiological responses to salinity stress (80 mM NaCl for 7 days) in seedlings of an O. rufipogon accession and two Italian O. sativa genotypes, Baldo (mildly tolerant) and Vialone Nano (sensitive). Under salt treatment, O. rufipogon showed the highest percentage of plants with no to moderate stress symptoms, displaying an unchanged shoot/root biomass ratio, the highest Na⁺ accumulation in roots, the lowest root and leaf Na⁺/K⁺ ratio, and highest leaf relative water content, leading to a better preservation of the plant architecture, ion homeostasis, and water status. Moreover, O. rufipogon preserved the overall leaf carbon to nitrogen balance and photosynthetic apparatus integrity. Conversely, Vialone Nano showed the lowest percentage of plants surviving after treatment, and displayed a higher reduction in the growth of shoots rather than roots, with leaves compromised in water and ionic balance, negatively affecting the photosynthetic performance (lowest performance index by JIP-test) and apparatus integrity. Baldo showed intermediate salt tolerance. Being O. rufipogon interfertile with O. sativa, it resulted a good candidate for pre-breeding towards salt-tolerant lines.

This report presents the activities and outcomes of an educational project aimed at promoting sustainable food awareness among high-school students in Italy through the active contributions from young researchers, profit partners and school educators. The project involved two final-year classes—one from a scientific lyceum and one from a technical chemistry institute—and integrated theoretical lessons, laboratory activities, and experiential learning focused on planetary boundaries, sustainable diets, and alternative proteins such as from algae and insects. To assess the impact of the project, pre- and post-intervention questionnaires were administered and are here discussed. The intervention significantly enhanced the students’ cognitive and affective engagement both during the sessions and in the immediate aftermath, as evidenced by elevated levels of satisfaction and retention of key concepts. Overall, the project fostered great environmental awareness and openness to sustainable food choices, demonstrating the potential of targeted hands-on educational programs to influence both attitudes and behaviours in younger generations of western high-income countries. The project serves as a replicable model of a transdisciplinary approach for integrating Education for Sustainable Development (ESD) and education for Planetary Health into secondary school curricula.

Nitrate is the dominant nitrogen source for marine microalgae, yet how it is taken up remains poorly understood in many ecologically and biotechnologically relevant species. Here we show that NITRATE TRANSPORTER 2.2 (NRT2.2) is the principal nitrate transporter of the oleaginous marine microalga Nannochloropsis oceanica . N. oceanica encodes only two NRT2 proteins and, unlike land plants and green algae, lacks a recognizable homolog of NITRATE ASSIMILATION-RELATED 2 (NAR2), the partner protein that green-lineage NRT2s require for activity and plasma membrane targeting. CRISPR knock-outs and confocal imaging showed that NRT2.2 is located at the plasma membrane and is required for nitrate uptake, whereas its paralog NRT2.1 cannot compensate for its loss. When nitrate was resupplied after nitrogen starvation, nrt2.2 mutants did not take up nitrate and did not resume growth, while they recovered normally with ammonium. Their photosystem II efficiency fell below that of fully nitrogen-starved wild-type cells, and chlorophyll content was reduced, while total protein remained stable. Fixed carbon was redirected into storage, with lipids and carbohydrates accumulating above the levels of all strains after 3 days of nitrogen starvation. Loss of NRT2.2 therefore mimics a prolonged nitrogen starvation, even though nitrate is available. Because nitrate was present but could not be used, recovery from starvation depends on the capacity to take up nitrate, not only on its availability. In the ocean, where nitrate is depleted for long periods and resupplied episodically, NRT2.2 is thus likely to set how quickly Nannochloropsis can use new nitrate inputs and resume growth.