Legumes overcome nitrogen shortage by developing root nodules in which symbiotic bacteria fix atmospheric nitrogen in exchange for host-derived carbohydrates and mineral nutrients. Nodule development involves the distinct processes of nodule organogenesis, bacterial infection, and the onset of nitrogen fixation. These entail profound, dynamic gene expression changes, notably contributed to by microRNAs (miRNAs). Here, we used deep-sequencing, candidate-based expression studies and a selection of Lotus japonicus mutants uncoupling different symbiosis stages to identify miRNAs involved in symbiotic nitrogen fixation. Induction of a noncanonical miR171 isoform, which targets the key nodulation transcription factor Nodulation Signaling Pathway2, correlates with bacterial infection in nodules. A second candidate, miR397, is systemically induced in the presence of active, nitrogen-fixing nodules but not in that of noninfected or inactive nodule organs. It is involved in nitrogen fixation-related copper homeostasis and targets a member of the laccase copper protein family. These findings thus identify two miRNAs specifically responding to symbiotic infection and nodule function in legumes.

One of the most important challenges that agriculture faces is sustainable water management and its adaptation to climate change. This adaptation is more important in regions where recurrent draughts and overexploitation of water resources happen. However, historical irrigation systems, such as the Real Acequia de Moncada (RAM) in Valencia, have found innovative approaches to deal with this phenomenon. This paper analyzes the case of Massamagrell and Puçol, which reused the treated waste-water of the closest waste-water treatment plant (WWTP). The study focused from a circular economy perspective on the technological, agronomical, and social implications of this decision. Results show that there are clear benefits for both farmers and WWTP managers. On the one hand, additional nutrients and regularity in their water supply benefit farmers. On the other, WWTP managers can reuse the treated effluent in the system, contributing to the closure of the water cycle and avoiding pumping the treated water into the sea. However, more detailed information and coordination is needed among the different stakeholders. Questions regarding the illegal connection of waste pipes with the traditional irrigation or the payment of pumping costs for reuse have gone unanswered, and there is a need for better reflection from all stakeholders.

Capsicum peppers (Capsicum spp.), especially C. annuum L., are one of the most important vegetables and spices in the world and their fruits are used in a range of food dishes, to provide aroma and flavor. Pungency has been largely studied, while studies on the volatile fraction are more recent and less diverse. A considerable varietal diversity among peppers has been reported in terms of the aroma quality and the qualitative and quantitative variation in the volatile fraction, particularly in fully ripe fruits, which encompass most diverse food applications and aroma profiles. Thus, a study was designed to study the inheritance of the volatile fractions in peppers and to determine if they can be improved by breeding strategies. The volatile fraction of 175 samples of ripe fruits from a diverse collection of peppers, encompassing a range of varietal types and aroma qualities, were isolated by headspace-solid-phase microextraction (HS-SPME) and analyzed by gas chromatography–mass spectrometry (GC–MS). A diverse profile of volatiles including terpenoids, esters, alkanes, and several aldehydes and alcohols, was found among the evaluated accessions. Our findings indicated that, in most cases, hybridization provided higher amounts of total volatiles and a more complex composition, particularly in the pericarp. In addition, the volatile fraction can be inherited from the parents to the offspring, as most individual volatiles in hybrids, especially major volatiles, were present in at least one of the parents, following intermediate (levels between parents) or transgressive (levels higher than the best parent) inheritance. De novo compounds (present in the hybrid, absent in the parents) were found in many samples. Comparatively, placental tissues had higher total and individual volatile levels compared with the pericarp in most parent accessions and hybrids, which must be considered by breeders if this part of the fruit is included in food formulations. By combining parent lines with complementary volatile fractions, hybridization offers a feasible method to improve the volatile composition of ripe fruits in Capsicum peppers.