Biochar enhances the growth and physiological characteristics of Medicago sativa, Amaranthus caudatus and Zea mays in saline soils

Biochar is a promising solution to alleviate the negative impacts of salinity stress on agricultural production. Biochar derived from food waste effect was investigated on three plant species, Medicago sativa, Amaranthus caudatus, and Zea mays, under saline environments. The results showed that biochar improved significantly the height by 30%, fresh weight of shoot by 35% and root by 45% of all three species compared to control (saline soil without biochar adding), as well as enhanced their photosynthetic pigments and enzyme activities in soil. This positive effect varied significantly between the 3 plants highlighting the importance of the plant-biochar interactions. Thus, the application of biochar is a promising solution to enhance the growth, root morphology, and physiological characteristics of plants under salt-induced stress.

Maize multi-omics reveal leaf water status controlling of differential transcriptomes, proteomes and hormones as mechanisms of age-dependent osmotic stress response in leaves

Drought-induced osmotic stress severely affects the growth and yield of maize. However, the mechanisms underlying the different responses of young and old maize leaves to osmotic stress remain unclear. To gain a systematic understanding of age-related stress responses, we compared osmotic-stress-induced changes in maize leaves of different ages using multi-omics approaches. After short-term osmotic stress, old leaves suffered more severe water deficits than young leaves. The adjustments of transcriptomes, proteomes, and hormones in response to osmotic stress were more dynamic in old leaves. Metabolic activities, stress signaling pathways, and hormones (especially abscisic acid) responded to osmotic stress in an age-dependent manner. We identified multiple functional clusters of genes and proteins with potential roles in stress adaptation. Old leaves significantly accumulated stress proteins such as dehydrin, aquaporin, and chaperones to cope with osmotic stress, accompanied by senescence-like cellular events, whereas young leaves exhibited an effective water conservation strategy mainly by hydrolyzing transitory starch and increasing proline production. The stress responses of individual leaves are primarily determined by their intracellular water status, resulting in differential transcriptomes, proteomes, and hormones. This study extends our understanding of the mechanisms underlying plant responses to osmotic stress.

Maize-Azospirillum brasilense interaction: accessing maize's miRNA expression under the effect of an inhibitor of indole-3-acetic acid production by the plant

MicroRNA (miRNA) is a class of non-coding RNAs. They play essential roles in plants' physiology, as in the regulation of plant development, response to biotic and abiotic stresses, and symbiotic processes. This work aimed to better understand the importance of maize's miRNA during Azospirillum-plant interaction when the plant indole-3-acetic acid (IAA) production was inhibited with yucasin, an inhibitor of the TAM/YUC pathway. Twelve cDNA libraries from a previous Dual RNA-Seq experiment were used to analyze gene expression using a combined analysis approach. miRNA coding genes (miR) and their predicted mRNA targets were identified among the differentially expressed genes. Statistical differences among the groups indicate that Azospirillum brasilense, yucasin, IAA concentration, or all together could influence the expression of several maize's miRNAs. The miRNA's probable targets were identified, and some of them were observed to be differentially expressed. Dcl4, myb122, myb22, and morf3 mRNAs were probably regulated by their respective miRNAs. Other probable targets were observed responding to the IAA level, the bacterium, or all of them. A. brasilense was able to influence the expression of some maize's miRNA, for example, miR159f, miR164a, miR169j, miR396c, and miR399c. The results allow us to conclude that the bacterium can influence directly or indirectly the expression of some of the identified mRNA targets, probably due to an IAA-independent pathway, and that they are somehow involved in the previously observed physiological effects.