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Rice (Oryza sativa L.), an important food crop, necessitates more water to complete its life cycle than other crops. Therefore, there is a serious risk to rice output due to water-related stress. Drought stress results in morphological changes, including the inhibition of seed germination, reduced seeding growth, leaf area index, flag leaf area, increased leaf rolling, as well as the decrement of yield traits, such as plant height, plant biomass, number of tillers, and 1000-grain yield. Stress also causes the formation of reactive oxygen species (ROS) such as O2−, H2O2, and OH−, which promote oxidative stress in plants and cause oxidative damage. The process of oxidative degradation owing to water stress produces cell damage and a reduction in nutrient intake, photosynthetic rate, leaf area, RWC, WUE, and stomatal closure, which may be responsible for the decrement of the transpiration rate and plant dry matter under decreasing soil moisture. Plants have the ability to produce antioxidant species that can either be enzymatic (SOD, POD, CAT, GPX, APX) or non-enzymatic (AsA, GSH) in nature to overcome oxidative stress. During drought, several biochemical osmoprotectants, like proline, polyamines, and sugars, can be accumulated, which can enhance drought tolerance in rice. To meet the demands of an ever-growing population with diminishing water resources, it is necessary to have crop varieties that are highly adapted to dry environments, and it may also involve adopting some mitigation strategies. This study aims to assess the varying morphological, physiological, and biochemical responses of the rice plant to drought, and the various methods for alleviating drought stress. [ABSTRACT FROM AUTHOR]

Messenger RNA (mRNA) vaccines were pivotal in reducing severe acute respiratory syndrome 2 (SARS-CoV-2) infection burden, yet they have not demonstrated robust durability, especially in older adults. Here, we describe a molecular adjuvant comprising a lipid nanoparticle (LNP)–encapsulated mRNA encoding interleukin-12p70 (IL-12p70). The bioactive adjuvant was engineered with a multiorgan protection (MOP) sequence to restrict transcript expression to the intramuscular injection site. Admixing IL-12–MOP (CTX-1796) with the BNT162b2 SARS-CoV-2 vaccine increased spike protein–specific immune responses in mice. Specifically, the benefits of IL-12–MOP adjuvantation included amplified humoral and cellular immunity and increased immune durability for 1 year after vaccination in mice. An additional benefit included the restoration of immunity in aged mice to amounts comparable to those achieved in young adult animals, alongside amplification with a single immunization. Associated enhanced dendritic cell and germinal center responses were observed. Together, these data demonstrate that an LNP-encapsulated IL-12–MOP mRNA-encoded adjuvant can amplify immunogenicity independent of age, demonstrating translational potential to benefit vulnerable populations. Editor's summary: Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines were instrumental in curbing the COVID-19 pandemic, the immunity elicited by these vaccines has been shown to wane over time, especially in older adults. Thus, mRNA vaccines, much like their protein counterparts, may benefit from the addition of an adjuvant. Here, Brook et al. showed that the BNT162b2 SARS-CoV-2 mRNA vaccine did not elicit IL-12p70, an important immune mediator, in human blood. Adjuvantation of the BNT162b2 SARS-CoV-2 mRNA vaccine with an mRNA encoding IL-12p70 amplified humoral and cellular immune responses, including in aged mice, and enabled a reduced dose of vaccine mRNA needed to achieve the same antibody response seen without adjuvantation. Moreover, limiting expression of IL-12p70 or spike antigen to muscle tissue, through the use of a multiorgan protection (MOP) sequence, maintained the benefit of adjuvantation with the potential advantage of avoiding side effects caused by systemic transcript expression. These data support further development of this mRNA-based adjuvant and of MOP platforms. —Courtney Malo [ABSTRACT FROM AUTHOR]