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Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

Xue Wang, Jie Wang, Shujie Wu, Qingwei Ni, Peng Chen Department of Cardiology, The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, People’s Republic of ChinaCorrespondence: Peng ChenDepartment of Cardiology, The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Xueyuanxi Road, No. 109, Wenzhou, 325000, Zhejiang, People’s Republic of ChinaEmail wzcpu72@163.comBackground: The neutrophil percentage-to-albumin ratio (NPAR) is a systemic inflammation-based predictor associated with many diseases’ outcomes. Nevertheless, there are few studies on the relationship between NPAR and inflammatory markers, and more importantly, the prognostic value of NPAR in critically ill patients with cardiovascular disease (CVD) remains unknown.Methods: The data of this retrospective cohort study were from the Medical Information Mart data for Intensive Care III database (MIMIC-III) and the Second Affiliated Hospital of Wenzhou Medical University. Linear regression, logistic regression model, and Cox regression model were used to assess the associations between NPAR levels and length of stay, renal replacement therapy (RRT) use, and 30-day, 90-day and one-year mortality, respectively. The Pearson correlation coefficient was used to present the correlation between NPAR and C-reactive protein (CRP).Results: Our study included 1599 patients in MIMIC-III and 143 patients in the Second Affiliated Hospital of Wenzhou Medical University. The elevated NPAR was independently associated with increased 30-day, 90-day, and one-year all-cause mortality (adjusted HR, 95% CI:1.51 (1.02– 2.24); 1.61 (1.14– 2.28); 1.53 (1.15– 2.03); P trend = 0.0297; 0.0053; 0.0023; respectively), and it was also associated with increase the length of stay in hospital and ICU (β, 95% CI: 2.76 (1.26– 4.27); 1.54 (0.62– 2.47), respectively, both P trend < 0.001). We found that patients with higher NPA

Biological fertilizers based on microalgae have proven to be a successful alternative in the agricultural sector to reduce unnecessary chemicals that can have unwanted side effects. Previous studies have shown that microalgae have multiple effects on plants, such as inducing faster germination, promoting leaf and root growth, and increasing disease resistance. This study investigated the biocontrol and biological fertilizer abilities of natural highly CK-producer Chlamydomonas reinhardtii (Chl). A newly developed CRISPR/Cas9 Chl mutants (CK-deficit) were used to investigate the function of cytokinins (CKs) in Chl-mediated bacterial-induced resistance and plant seed germination and drought tolerance. In wild type CC125, there are 6156,6 pmol/g total CKs (including 30.2% CKs bases and 69.8% CKs nucleotides), 55.5% iP- type, 44.3% cZ-type, 0.2% tZ type were found by LC-MS. The CKs level of the isopentenyl transferase (IPT) mutants and the Lonely Guy Gene (LOG) mutants are 11,7 pmol/g and 1688,2 pmol/g, respectively. The biocontrol results showed the promotion of Nicotiana tabacum cultivar SR1 (NT) resistance to the Pseudomonas syringae pv. Tabaci (PstT) after infiltration with the wild-type strains of Chl. On the other hand, mutant strains deficient in the production and signaling of CKs showed a reduction in resistance promotion. Nevertheless, mutants indicated positive stimulation effects on drought tolerance in Arabidopsis. These results prove that CKs are an essential part of microalgae's ability to promote resistance to pathogens. Meanwhile, moderate CKs producing mutant Chl strains are good candidates as biofertilizers to improve the drought resistance in plants.

Biological fertilizers based on microalgae have proven to be a successful alternative in the agricultural sector to reduce unnecessary chemicals that can have unwanted side effects. Previous studies have shown that microalgae have multiple effects on plants, such as inducing faster germination, promoting leaf and root growth, and increasing disease resistance. This study investigated the biocontrol and biological fertilizer abilities of natural highly CK-producer Chlamydomonas reinhardtii (Chl). A newly developed CRISPR/Cas9 Chl mutants (CK-deficit) were used to investigate the function of cytokinins (CKs) in Chl-mediated bacterial-induced resistance and plant seed germination and drought tolerance. In wild type CC125, there are 6156,6 pmol/g total CKs (including 30.2% CKs bases and 69.8% CKs nucleotides), 55.5% iP- type, 44.3% cZ-type, 0.2% tZ type were found by LC-MS. The CKs level of the isopentenyl transferase (IPT) mutants and the Lonely Guy Gene (LOG) mutants are 11,7 pmol/g and 1688,2 pmol/g, respectively. The biocontrol results showed the promotion of Nicotiana tabacum cultivar SR1 (NT) resistance to the Pseudomonas syringae pv. Tabaci (PstT) after infiltration with the wild-type strains of Chl. On the other hand, mutant strains deficient in the production and signaling of CKs showed a reduction in resistance promotion. Nevertheless, mutants indicated positive stimulation effects on drought tolerance in Arabidopsis. These results prove that CKs are an essential part of microalgae's ability to promote resistance to pathogens. Meanwhile, moderate CKs producing mutant Chl strains are good candidates as biofertilizers to improve the drought resistance in plants.