Bacterial endophytome-mediated resistance in banana for the management of Fusarium wilt.

Banana (Musa spp.), a major cash and staple fruit crop in many parts of the world, is infected by Fusarium wilt, which contributes up to 100% yield loss and causes social consequences. Race 1 and race 2 of Panama wilt caused by Fusarium oxysporum f. sp. cubense (Foc) are prevalent worldwide and seriously affect many traditional varieties. The threat of Foc tropical race 4 (Foc TR4) is looming large in African counties. However, its incidence in India has been confined to Bihar (Katihar and Purnea), Uttar Pradesh (Faizabad), Madhya Pradesh (Burhanpur) and Gujarat (Surat). Management of Foc races by employing fungicides is often not a sustainable option as the disease spread is rapid and they negatively alter the biodiversity of beneficial ectophytes and endophytes. Besides, soil drenching with carbendazim/trifloxystrobin + tebuconazole is also not effective in suppressing the Fusarium wilt of banana. Improvement of resistance to Fusarium wilt in susceptible cultivars is being addressed through both conventional and advanced breeding approaches. However, engineering of banana endosphere with bacterial endophytes from resistant genotypes like Pisang lilly and YKM5 will induce the immune response against Foc, irrespective of races. The composition of the bacterial endomicrobiome in different banana cultivars is dominated by the phyla Proteobacteria, Bacteroidetes and Actinobacteria. The major bacterial endophytic genera antagonistic to Foc are Bacillus, Brevibacillus, Paenibacillus, Virgibacillus, Staphylococcus, Cellulomonas, Micrococcus, Corynebacterium, Kocuria spp., Paracoccus sp., Acinetobacter spp. Agrobacterium, Aneurinibacillus, Enterobacter, Klebsiella, Lysinibacillus, Micrococcus, Rhizobium, Sporolactobacillus, Pantoea, Pseudomonas, Serratia, Microbacterium, Rhodococcus, Stenotrophomonas, Pseudoxanthomonas, Luteimonas, Dokdonella, Rhodanobacter, Luteibacter, Steroidobacter, Nevskia, Aquicella, Rickettsiella, Legionella, Tatlockia and Streptomyces. These bacterial endophytes promote the growth of banana plantlets by solubilising phosphate, producing indole acetic acid and siderophores. Application of banana endophytes during the hardening phase of tissue-cultured clones serves as a shield against Foc. Hitherto, MAMP molecules of endophytes including flagellin, liposaccharides, peptidoglycans, elongation factor, cold shock proteins and hairpins induce microbe-associated molecular pattern (MAMP)-triggered immunity to suppress plant pathogens. The cascade of events associated with ISR and SAR is induced through MAPK and transcription factors including WRKY and MYC. Studies are underway to exploit the potential of antagonistic bacterial endophytes against Foc isolates and to develop an understanding of the MAMP-triggered immunity and metabolomics cross talk modulating resistance. This review explores the possibility of harnessing the potential bacterial endomicrobiome against Foc and developing nanoformulations with bacterial endophytes for increased efficacy against lethal pathogenic races of Foc infecting banana. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02833-5.

Understanding the molecular basis on the biological suppression of bacterial leaf blight of anthurium exerted by Bacillus subtilis (BIO3) through proteomic approach.

We attempted to study the antibacterial activity of rhizospheric Bacillus spp., to curb the bacterial blight of anthurium caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad). Twenty-eight bacterial isolates from rhizospheric regions were identified as different Bacillus spp. and Ochrobactrum sp. using 16S rRNA gene sequencing. B. subtilis BIO3 effectively inhibited the growth of Xad up to 1450.7 mm2, and extracted volatile organic metabolites from the isolate BIO3 inhibited the growth of Xad up to 1024 mm2. Tritrophic interaction of anthurium leaves bacterized with B. subtilis BIO3 and challenged with Xad resulted in the expression of 12 unique proteins compared to untreated control. Mascot Peptide Mass Fingerprint-based identification indicated that one was glutathione peroxidase, involved in defence mechanism, other six proteins were identified as leghemoglobin II, CTP synthase-like, predicted protein (Physcomitrella patens), centromere-associated protein E, grain size protein, and five proteins were hypothetical proteins. Foliar application with 1% liquid formulations (108 CFU/ml) of B. subtilis BIO3 significantly suppressed the bacterial leaf blight of anthurium up to 78% over untreated control and also increased the stem length and flower yield.

Flagellin of Bacillus amyloliquefaciens works as a resistance inducer against groundnut bud necrosis virus in chilli (Capsicum annuum L.).

Groundnut bud necrosis virus (GBNV), a member of the genus Tospovirus, has an extensive host range and is associated with necrosis disease of chilli (Capsicum annuum L.), which is a major threat to commercial production. Plant growth promoting rhizobacteria (PGPR) have been investigated for their antiviral activity in several crops and for their potential use in viral disease management. However, the microbial mechanisms associated with PGPR in triggered immunity against plant viruses have rarely been studied. To understand the innate immune responses activated by Bacillus spp. against GBNV, we studied microbe-associated molecular pattern (MAMP) triggered immunity (MTI) in chilli using transient expression of the flagellin gene of Bacillus amyloliquefaciens CRN9 from Agrobacterium clones, which also induced the expression of EAS1 gene transcripts coding for epi-aristolochene synthase, which is responsible for the accumulation of capsidiol phytoalexin. In addition, the transcript levels of WRKY33 transcription factor and salicylic acid (SA)-responsive defense genes such as NPR1, PAL, PO and SAR8.2 were increased. Jasmonate (JA)-responsive genes, viz., PDF, and LOX genes, were also upregulated in chilli plants challenged with GBNV. Further analysis revealed significant induction of these genes in chilli plants treated with B. amyloliquefaciens CRN9 and benzothiadiazole (BTH). The transcript levels of defense response genes and pathogenesis-related proteins were significantly higher in plants treated with Bacillus and BTH and remained significantly higher at 72 h post-inoculation and compared to the inoculated control. The plants treated with flagellin using the agrodrench method and exogenous treatment with B. amyloliquefaciens and BTH showed resistance to GBNV upon mechanical inoculation and a reduced virus titre which was confirmed by qPCR assays. Thus, transient expression of flagellin, a MAMP molecule from B. amyloliquefaciens CRN9, is able to trigger innate immunity and restrain virus growth in chilli via induced systemic resistance (ISR) activated by both the SA and JA/ET signalling pathways.

Papillary thyroid carcinoma: debate at rest.

INTRODUCTION: Papillary thyroid cancer (PTC) is the most common well-differentiated cancer of the thyroid and is one of the fastest growing group of cancers probably because of the increased use of ultrasound (HRUSG) in the evaluation of the thyroid in recent years. MATERIALS AND METHODS: A MEDLINE and OVID database search was performed to collect information on papillary thyroid carcinoma. Recently published consensus guidelines were also used as an additional resource. CONCLUSIONS: The controversy regarding the extent of thyroidectomy in patients of PTC is relatively settled, with total thyoidectomy being the preferred approach with nodules> 1.5 cm in size. Lymph node (LN) metastases do not seem to affect the overall survival, but they do increase the recurrence rate. It is worthwhile to offer LN dissection at initial surgery if LNs are ultrasonologically diagnosed to harbor malignancy. In experts hands, the rate of recurrent laryngeal nerve injury and hypoparathyroidism is negligible in a neck dissection in initial surgery and remains negligible if carried out in a redo or completion scenario.