Mineral Solubilizing Rhizobacterial Strains Mediated Biostimulation of Rhodes Grass Seedlings.

Minerals play a dynamic role in plant growth and development. However, most of these mineral nutrients are unavailable to plants due to their presence in fixed forms, which causes significant losses in crop production. An effective strategy to overcome this challenge is using mineral solubilizing bacteria, which can convert insoluble forms of minerals into soluble ones that plants can quickly assimilate, thus enhancing their availability in nutrient-depleted soils. The main objective of the present study was to isolate and characterize mineral solubilizing rhizobacteria and to assess their plant growth-promoting potential for Rhodes grass. Twenty-five rhizobacterial strains were isolated on a nutrient agar medium. They were characterized for solubilization of insoluble minerals (phosphate, potassium, zinc, and manganese), indole acetic acid production, enzymatic activities, and various morphological traits. The selected strains were also evaluated for their potential to promote the growth of Rhodes grass seedlings. Among tested strains, eight strains demonstrated strong qualitative and quantitative solubilization of insoluble phosphate. Strain MS2 reported the highest phosphate solubilization index, phosphate solubilization efficiency, available phosphorus concentration, and reduction in medium pH. Among tested strains, 75% were positive for zinc and manganese solubilization, and 37.5% were positive for potassium solubilization. Strain MS2 demonstrated the highest quantitative manganese solubilization, while strains MS7 and SM4 reported the highest solubilization of zinc and potassium through acidifying their respective media. The strain SM4 demonstrated the most increased IAA production in the presence and absence of L-tryptophan. The majority of strains were positive for various enzymes, including urease, catalase protease, and amylase activities. However, these strains were negative for coagulase activity except strains SM7 and MS7. Based on 16S rRNA gene sequencing, six strains, namely, SM2, SM4, SM5, MS1, MS2, and MS4, were identified as Bacillus cereus, while strains SM7 and MS7 were identified as Staphylococcus saprophyticus and Staphylococcus haemolyticus. These strains significantly improved growth attributes of Rhodes grass, such as root length, shoot length, and root and shoot fresh and dry biomasses compared to the uninoculated control group. The present study highlights the significance of mineral solubilizing and enzyme-producing rhizobacterial strains as potential bioinoculants to enhance Rhodes grass growth under mineral-deficient conditions sustainably.

Prognostic Significance of Substance P/Neurokinin 1 Receptor and Its Association with Hormonal Receptors in Breast Carcinoma.

Expression and immunolocalization of Substance P (SP)/Neurokinin-1 Receptor (NK-1R) in breast carcinoma (BC) patients and its association with routine proliferative markers (ER, PR, HER2/neu, and Ki-67) were evaluated. A cross-sectional study was performed on 34 cases of BC. There were 23 cases of group A (grade III), 8 of group B (grade II), and only 3 cases of group C (grade I). All samples were then processed for SP and NK-1R immunohistochemistry for few cases. 14/23 cases (61%) of group A, 7/8 cases (88%) of group B, and 2/3 (67%) cases of group C were SP positive. Overall, strong staining (≥10% tumor cells), labeled as "+3," was observed in 9/14 (64.2%) cases of group A and 1/8 (12.5%) cases of group B. Moderate staining labelled as "+2" (in ≥10% tumor cells) was observed in 3/14 (21.4%) cases of group A and 4/8 (50%) cases of group B. Weak positive staining "+1" was observed in only 2/14 (14.28%) cases of group A, 2/8 (25%) cases of group B, and all 2/2 (100%) cases of group C. SP and NK-1R are overexpressed in breast carcinomas, and there is significant association between the grade of tumor and their overexpression.

Communication of plants with microbial world: Exploring the regulatory networks for PGPR mediated defense signaling.

Agricultural manipulation of potentially beneficial rhizosphere microbes is increasing rapidly due to their multi-functional plant-protective and growth related benefits. Plant growth promoting rhizobacteria (PGPR) are mostly non-pathogenic microbes which exert direct benefits on plants while there are rhizosphere bacteria which indirectly help plant by ameliorating the biotic and/or abiotic stress or induction of defense response in plant. Regulation of these direct or indirect effect takes place via highly specialized communication system induced at multiple levels of interaction i.e., inter-species, intra-species, and inter-kingdom. Studies have provided insights into the functioning of signaling molecules involved in communication and induction of defense responses. Activation of host immune responses upon bacterial infection or rhizobacteria perception requires comprehensive and precise gene expression reprogramming and communication between hosts and microbes. Majority of studies have focused on signaling of host pattern recognition receptors (PRR) and nod-like receptor (NLR) and microbial effector proteins under mining the role of other components such as mitogen activated protein kinase (MAPK), microRNA, histone deacytylases. The later ones are important regulators of gene expression reprogramming in plant immune responses, pathogen virulence and communications in plant-microbe interactions. During the past decade, inoculation of PGPR has emerged as potential strategy to induce biotic and abiotic stress tolerance in plants; hence, it is imperative to expose the basis of these interactions. This review discusses microbes and plants derived signaling molecules for their communication, regulatory and signaling networks of PGPR and their different products that are involved in inducing resistance and tolerance in plants against environmental stresses and the effect of defense signaling on root microbiome. We expect that it will lead to the development and exploitation of beneficial microbes as source of crop biofertilizers in climate changing scenario enabling more sustainable agriculture.

In-planta expression of insecticidal proteins provides protection against lepidopteran insects.

The development of advanced biotechnological control strategies opens a new era of environment friendly pest management. The current study is part of such an effort, in which we developed a control strategy based on gene pyramiding that confers broad-spectrum resistance against lepidopteran (Helicoverpa armigera and Spodoptera litura) and hemipteran (Myzus persicae, Phenacoccus solenopsis, and Bemisia tabaci) insect pests. Previously, we reported a double gene construct expressing Hvt and lectin in tobacco (Nicotiana tabacum) plants under phloem specific promoters which confers resistance against hemipteran insects. Here we extended our studies by evaluating the advanced generation of these tobacco plants expressing hvt-lectin against lepidopteran insects. Tobacco plants expressing both toxins were tested against H. armigera and S. litura. Insect bioassay results showed 100% mortality of H. armigera within 48-72 hours and 100% mortality of S. litura within 72-96 hours. Our results suggest that the use of both toxins as a gene pyramiding strategy to control both lepidopteran and hemipterans insects on commercial basis to reduce the use of chemical pesticides.

Computational and biological characterization of fusion proteins of two insecticidal proteins for control of insect pests.

Sucking pests pose a serious agricultural challenge, as available transgenic technologies such as Bacillus thuringiensis crystal toxins (Bt) are not effective against them. One approach is to produce fusion protein toxins for the control of these pests. Two protein toxins, Hvt (ω-atracotoxin from Hadronyche versuta) and onion leaf lectin, were translationally fused to evaluate the negative effects of fusion proteins on Phenacoccus solenopsis (mealybug), a phloem-feeding insect pest. Hvt was cloned both N-terminally (HL) and then C-terminally (LH) in the fusion protein constructs, which were expressed transiently in Nicotiana tabacum using a Potato Virus X (PVX) vector. The HL fusion protein was found to be more effective against P. solenopsis, with an 83% mortality rate, as compared to the LH protein, which caused 65% mortality. Hvt and lectin alone caused 42% and 45%, respectively, under the same conditions. Computational studies of both fusion proteins showed that the HL protein is more stable than the LH protein. Together, these results demonstrate that translational fusion of two insecticidal proteins improved the insecticidal activity relative to each protein individually and could be expressed in transgenic plants for effective control of sucking pests.

A transgenic approach to control hemipteran insects by expressing insecticidal genes under phloem-specific promoters.

The first generation transgenic crops used strong constitutive promoters for transgene expression. However, tissue-specific expression is desirable for more precise targeting of transgenes. Moreover, piercing/sucking insects, which are generally resistant to insecticidal Bacillus thuringiensis (Bt) proteins, have emerged as a major pests since the introduction of transgenic crops expressing these toxins. Phloem-specific promoters isolated from Banana bunchy top virus (BBTV) were used for the expression of two insecticidal proteins, Hadronyche versuta (Blue Mountains funnel-web spider) neurotoxin (Hvt) and onion leaf lectin, in tobacco (Nicotiana tabacum). Here we demonstrate that transgenic plants expressing Hvt alone or in combination with onion leaf lectin are resistant to Phenacoccus solenopsis (cotton mealybug), Myzus persicae (green peach aphids) and Bemisia tabaci (silver leaf whitefly). The expression of both proteins under different phloem-specific promoters resulted in close to 100% mortality and provided more rapid protection than Hvt alone. Our results suggest the employment of the Hvt and onion leaf lectin transgenic constructs at the commercial level will reduce the use of chemical pesticides for control of hemipteran insect pests.

Regional changes in the sequence of cotton leaf curl multan betasatellite.

Cotton leaf curl disease (CLCuD) in Pakistan and northwestern India is caused by monopartite begomoviruses in association with an essential, disease-specific satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Following a recent upsurge in CLCuD problems in Sindh province (southern Pakistan), sequences of clones of CLCuMB were obtained from Sindh and Punjab province (central Pakistan), where CLCuD has been a problem since the mid-1980s. The sequences were compared to all sequences of CLCuMB available in the databases. Analysis of the sequences shows extensive sequence variation in CLCuMB, most likely resulting from recombination. The range of sequence variants differ between Sindh, the Punjab and northwestern India. The possible significance of the findings with respect to movement of the CLCuD between the three regions is discussed. Additionally, the lack of sequence variation within the only coding sequence of CLCuMB suggests that the betasatellite is not involved in resistance breaking which became a problem after 2001 in the Punjab and subsequently also in northwestern India.