BMC Plant Biology最新文献

Methods to assure the health of crops owe their efficacy to the extent of which we understand the ecology and biology of environmental microorganisms, as well as the conditions under which their interactions can lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant-associated microorganisms have been reduced to an agro-centric focus. Microbial diversity is now known to be more diverse than previously thought in both environmental and host-associated habitats. This concept includes many lineages that are (or may become) host associated and can form part of pathobiomes, occasionally playing role in health condition of different plants. Surveys and samplings were conducted in natural habitats of Astragalus verus in Iran to monitor the status of prokaryotic agents associated with this herb. Two Gram-negative brownish-gray colored bacterial strains were isolated from plants, with symptoms suspected to presence of a living microorganism in two different sampling areas. The strains (namely D3 and M11) were identified as members of the genus Pseudomonas based on phenotypic features e.g., morphological characteristics, pigmentation, LOPAT scheme, etc. Precise phylogenetic position and taxonomic status of the strains were determined using the phylogeny of gyrB, rpoB and rpoD gene sequences. Accordingly, the two strains were classified within the Pseudomonas fluorescens subgroup in P. fluorescens lineage and clustered in a sister clade next to the type strain of Pseudomonas cedrina subsp. cedrina (DSM 17516). They were tested for sensitivity to copper compounds and various antibiotics with different targets and mechanisms of action. Additionally, the possibility of symptom development by these strains on some nearby and distant plants was investigated, and in many tested cases, some lesions were detected. Overall, these evidences suggest that A. verus may serve as a previously unreported ecological habitat for P. cedrina. It is hoped that this pioneering study of bacterial agents present in A. verus pathobiome will open up new horizons for investigating other existing agents associated with this herb, a plant species providing vital ecosystem functions for de-desertification, rangeland management and restoration, and yet less studied.

KNO₃, an inorganic salt, plays a crucial role in regulating growth, stress responses, and various physiological processes, including seed germination and root architecture. Previous research has established the role of KNO₃ in improving the seed quality, but the specific mechanism which contributes to the seed enhancement and nutrient acquisition remains uninvest gated. Priming with potassium nitrate (KNO₃) is a promising strategy to enhance seed quality and seedling performance under suboptimal conditions. The effects of KNO₃ priming on both seed metabolism and germination and early seed growth in tomato (Solanum lycopersicum) is investigated in this study. Seeds were seeded with four KNO₃-primed tomato in varying concentrations (0.1%, 0.5%, 1% and 1.5%) for 21 h. In this present study, 1% of KNO₃ is the most effective concentration, which significantly improves germination percentage, seedling dry weight, germination speed, and seed vigour indices compared to both control and hydroprimed seeds. Validation across three varieties of tomato further confirmed the effectiveness of 1.0% KNO₃ priming on seed quality. It regulates seed physiological activity by increasing total chlorophyll, total soluble protein, total soluble sugar, and proline levels, along with elevated antioxidant enzyme activities such as superoxide dismutase (SOD) in primed seedlings. It helps in reducing the deterioration of the membrane, indicated by a reduction in MDA content. Root scanning in three varieties showed further enhancement in root morphology, indicated by elevated levels of average diameter, total root volume, root length, total surface area, and nodule tips. The present study also focuses on emphasizing the benefit of seed quality and root architecture of tomato by using KNO₃ priming, and thereby serve as an efficient means to enhance both seedling establishment and seed performance.

Background: The broomrape Phelipanche aegyptiaca (Orobanchaceae) is a root holoparasitic plant that acquires carbon (C), nitrogen (N) and phosphorus (P) from host plants. When the host plant suffers from nutrient deficiency, how broomrape responds and the underlying mechanisms remain to be elucidated.

Results: Here, using tobacco (Nicotiana tabacum) and P. aegyptiaca as a parasitization system, we show that under the full nutrient, N-, or P-depleted conditions, broomrape parasitism resulted in increased levels of resources (C, N, and P) in the belowground parts (root and broomrape) of the parasitized plants, compared with the roots of non-parasitized plants. By providing the parasitization systems with different N and P levels, we found that broomrape growth is associated with that of the host root. Genetic and transcriptomic analysis indicated that under the N or P stress conditions, the strigolactone, reactive oxygen species, abscisic acid, and miR399 pathway in the tobacco host positively regulate the transcriptome response and growth of broomrape, suggesting that some certain systemic signals controlled by these pathways through together or parting form are transferred from host to broomrape and modulate broomrape physiology.

Conclusions: This study expands our understanding of the nutrient stress physiology of parasitization systems and highlights the roles of these host signaling pathways during the communications between hosts and parasites under nutrient stresses.