New reports of pathogen spectrum associated with bulb rot and their interactions during the development of rot in tulip.

Bulb rot, a highly damaging disease of tulip plants, has hindered their profitable cultivation worldwide. This rot occurs in both field and storage conditions posing significant challenges. While this disease has been attributed to a range of pathogens, previous investigations have solely examined it within the framework of a single-pathogen disease model. Our study took a different approach and identified four pathogens associated with the disease: Fusarium solani, Penicillium chrysogenum, Botrytis tulipae, and Aspergillus niger. The primary objective of our research was to examine the impact of co-infections on the overall virulence dynamics of these pathogens. Through co-inoculation experiments on potato dextrose agar, we delineated three primary interaction patterns: antibiosis, deadlock, and merging. In vitro trials involving individual pathogen inoculations on tulip bulbs revealed that B. tulipae,was the most virulent and induced complete bulb decay. Nonetheless, when these pathogens were simultaneously introduced in various combinations, outcomes ranged from partial bulb decay to elongated rotting periods. This indicated a notable degree of antagonistic behaviour among the pathogens. While synergistic interactions were evident in a few combinations, antagonism overwhelmingly prevailed. The complex interplay of these pathogens during co-infection led to a noticeable change in the overall severity of the disease. This underscores the significance of pathogen-pathogen interactions in the realm of plant pathology, opening new insights for understanding and managing tulip bulb rot.

Genome-wide characterization and development of SSR markers for genetic diversity analysis in northwestern Himalayas Walnut (Juglans regia L.).

In the present study, we designed and validated genome-wide polymorphic SSR markers (110 SSRs) by mining the walnut genome. A total of 198,924 SSR loci were identified. Among these, successful primers were designed for 162,594 (81.73%) SSR loci. Dinucleotides were the most predominant accounting for 88.40% (175,075) of total SSRs. The SSR frequency was 377.312 SSR/Mb and it showed a decreasing trend from dinucleotide to octanucleotide motifs. We identified 20 highly polymorphic SSR markers and used them to genotype 72 walnut accessions. Over all, we obtained 118 alleles that ranged from 2 to 12 with an average value of 5.9. The higher SSR PIC values indicate their robustness in discriminating walnut genotypes. Heat map, PCA, and population structure categorized 72 walnut genotypes into 2 distinct clusters. The genetic variation within population was higher than among population as inferred by analysis of molecular variance (AMOVA). For walnut improvement, it is necessary to have a large repository of SSRs with high discriminative power. The present study reports 150,000 SSRs, which is the largest SSR repository for this important nut crop. Scientific communities may use this repository for walnut improvement such as QTL mapping, genetic studies, linkage map construction, and marker-assisted selection. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03563-6.

Fusarium chlamydosporum, causing wilt disease of chili (Capsicum annum L.) and brinjal (Solanum melongena L.) in Northern Himalayas: a first report.

Chili (Capsicum annuum L.) and brinjal (Solanum melongena L.) are the most widely grown solanaceous crops in the world. However, their production has reduced over several years due to the attack of various fungal and bacterial pathogens and various abiotic factors. Still, the major constrain in their production are pathogens with fungal etiology, especially the fungal wilt of solanaceous crops. Fusarium oxysporum and Fusarium solani have been previously identified as the pathogens causing wilt disease in chili and brinjal. Recently, a new fungal pathogen F. equiseti has been reported as the causal agent of wilt disease infecting chili. The current study focused on identifying fungal pathogens associated with the wilted plants of chili and brinjal, collected from different parts of the Himalayan region of Kashmir valley, through morpho-cultural and molecular characterization. DNA extraction, PCR amplification, and sequencing were performed on various isolates. DNA barcoding using the internal transcribed spacer region (ITS) was used to identify the pathogen followed by the pathogenicity test. Further confirmation of the pathogen was done by sequencing of transcription elongation factor (TEF) and Calmodulin (CAL2). In current study Fusarium chlamydosporum has been reported as the wilt causing pathogen of chili and brinjal for the first time in Kashmir Himalayas.

Marker-assisted introgression of three dominant blast resistance genes into an aromatic rice cultivar Mushk Budji.

Modern high yielding rice varieties have replaced most of the traditional cultivars in recent past. Mushk Budji, is one such short grained landrace known for its aroma and exquisite quality, however, is highly susceptible to blast disease that has led to considerable decline in its area. Mushk Budji was crossed to a triple-gene donor line, DHMAS 70Q 164-1b and followed through marker-assisted foreground and background selection in first and second backcross generations that helped to incorporate blast resistance genes Pi54, Pi1 and Pita. Marker-assisted background selection was carried out using 78 SSR and STS markers that helped to reduce linkage drag around the genes Pi54, Pi1 and Pita to 2.74, 4.60 and 2.03 Mb, respectively. The three-gene lines in BC2F2:3 were genotyped using 50 K SNP chip and revealed more than 92% genome similarity to the RP. 2-D gel assay detected differentially expressing 171 protein spots among a set of backcross derived lines, of which 38 spots showing match score of 4 helped us to calculate the proteome recovery. MALDI-TOF analysis helped to detect four significant proteins that were linked to quality and disease resistance. The improved lines expressed resistance to blast under artificial and natural field conditions.