Biology subjects

Faigenboim, A.

Publications and source records attributed to Faigenboim, A..

6 recordsLinked to original sources

bioRxiv2026

Graph-based pangenome provides insights into the adaptive evolution of Cucurbita pepo

Understanding how crops respond to environmental variation is crucial for biodiversity conservation and food security. Cucurbita pepo (pumpkin, squash, gourd) is one of the first domesticated crop species and exhibits remarkable phenotypic and ecological diversity, making it a powerful system for investigating the genomic basis of adaptation. Here, we constructed a graph-based C. pepo pangenome using nine chromosome-level assemblies and identified 229,431 high-confidence structural variants (SVs) that were genotyped across 206 wild and cultivated accessions. Our results demonstrate that C. pepo underwent parallel domestication, with two deeply diverged gene pools independently giving rise to the pepo and ovifera cultivated lineages, followed by expansion into diverse environments that produced strong signatures of differentiation largely mediated by young adaptive alleles. Single-nucleotide polymorphisms (SNPs) and SVs contribute complementary dimensions of environmental responsiveness. Biogeographical modeling predicts continued range contraction of wild relatives and elevated genetic offset in Eastern North American populations under projected future climates. Populations with higher genetic load harbor fewer adaptive variants and exhibit greater predicted maladaptation, indicating that deleterious mutations constrain adaptive potential. These findings highlight how genomic variants, adaptive diversity, and genetic load together shape environmental adaptation and inform conservation and crop improvement.

genomics↗

bioRxiv2025

Dynamics in microbial communities associated with the development of soil fatigue in banana

Soil fatigue, well-documented in various crops, presents a significant challenge to banana production by causing fast and then gradual declines in plant growth and yield over years of cultivation. Despite its impact on profitability, the underlying mechanisms driving soil fatigue remain poorly understood; however, a strong link to shifts in the soil microbiome has been suggested. We investigated the dynamics of microbial communities in relation to soil fatigue, using a novel semi-controlled outdoor experimental system. Soils at different stages of fatigue (0 to 42 months of banana cultivation) were generated in large containers filled with initially healthy soil. Banana plants grown in these soils were replaced with new plants which showed soil age-dependent growth. Three months postplanting, soil and root samples were collected for analyses of soil parameters and microbial community composition using bacterial (16S) and fungal (ITS) amplicon sequencing. We identified minor age-related shifts in mainly pH, potassium, and organic matter in the soil. While alpha diversity remained unchanged, significant shifts in bacterial and fungal community composition were observed in fatigued soils. Notably, the relative abundance of bacterial families such as Flavobacteriaceae, Pseudomonaceae, and Acidibacter increased, as did some fungal taxa (many from groups with known pathogens)-Ceratobasidiaceae (including Rhizoctonia), Dothideomycetes, and Stachybotryaceae. Simultaneously, the relative abundance of bacterial families with known beneficial members, including Gemmatimonadaceae, Moraxellaceae, Sphingomonadaceae, and Azospirillaceae, as well as symbiotic fungal taxa such as Glomeraceae and Lasiosphaeriaceae, declined. Thus, soil fatigue may be correlated to proliferation of pathogenic populations and a loss of beneficial microorganisms.

ecology↗

bioRxiv2022

Two independent loss-of-function mutations in anthocyanidin synthase homeologous genes make sweet basil all green

Sweet basil, Ocimum basilicum L., is an important culinary herb grown worldwide. Although basil is green, many landraces, breeding lines and exotic cultivars have purple stems and flowers. This anthocyanins pigmentation is unacceptable in the traditional Italian basil. We used the recently published sweet basil genome to map quantitative trait loci (QTL) for flower and stem color in a bi-parental F2 population. It was found that the pigmentation is governed by a single QTL, harboring an anthocyanidin synthase (ANS) gene. Further analysis revealed that the basil genome harbors two homeologous ANS genes, each carrying a loss-of-function mutation. ObANS1 carries a 1-bp insertion, and ObANS2 carries a missense mutation within the active site. In the purple-flower parent, ANS1 is functional and ANS2 carries a nonsense mutation. The functionality of the active allele was validated by complementation in an Arabidopsis ANS mutant. Moreover, we have restored the functionality of the missense-mutated ANS2 using site-directed activation. We found that the non-functional alleles were expressed to similar levels as the functional allele, suggesting polyploids invest futile effort in expressing non-functional genes, harming their superior redundancy. We show here we can harness basils genomics and genetics to understand the basic mechanism of metabolic traits.

plant biology↗

bioRxiv2021

Florigen governs shoot regeneration.

It is widely known that during the reproductive stage (flowering), plants do not root well. Most protocols of shoot regeneration in plants utilize juvenile tissue. Adding these two realities together encouraged us to studied the role of florigen in shoot regeneration. Mature tobacco tissue that expresses the endogenous tobacco florigen mRNA regenerates poorly, while juvenile tissue that does not express the florigen regenerates shoots well. Inhibition of Nitric Oxide (NO) synthesis reduced shoot regeneration as well as promoted flowering and increased tobacco florigen level. In contrast, the addition of NO (by way of NO donor) to the tissue increased regeneration, delayed flowering, reduced tobacco florigen mRNA. Ectopic expression of florigen genes in tobacco or tomato decreased regeneration capacity significantly. Overexpression pear PcFT2 gene increased regeneration capacity. During regeneration, florigen mRNA was not changed. We conclude that florigen presence in mature tobacco leaves reduces roots and shoots regeneration and is the possible reason for the age-related decrease in regeneration capacity.

plant biology↗

bioRxiv2019

Multi-allelic APRR2 Gene is Associated with Fruit Pigment Accumulation in Melon and Watermelon

Color and pigment content are important aspects of fruit quality and consumer acceptance of cucurbit crops. Here, we describe the independent mapping and cloning of a common causative APRR2 gene regulating pigment accumulation in melon and watermelon. We initially show that the APRR2 transcription factor is causative for the qualitative difference between dark and light green rind in both crops. Further analyses establish the link between sequence or expression level variations in the CmAPRR2 gene and pigments content in the rind and flesh of mature melon fruits. GWAS of young fruit rind color in a panel composed of 177 diverse melon accessions did not result in any significant association, leading to an earlier assumption that multiple genes are involved in shaping the overall phenotypic variation at this trait. Through resequencing of 25 representative accessions and allelism tests between light rind accessions, we show that multiple independent SNPs in the CmAPRR2 gene are causative for the light rind phenotype. The multi-haplotypic nature of this gene explain the lack of detection power obtained through GBS-based GWAS and confirm the pivotal role of this gene in shaping fruit color variation in melon. This study demonstrates the power of combining bi- and multi-allelic designs with deep sequencing, to resolve lack of power due to high haplotypic diversity and low allele frequencies. Due to its central role and broad effect on pigment accumulation in fruits, the APRR2 gene is an attractive target for carotenoids bio-fortification of cucurbit crops.

plant biology↗

bioRxiv2017

Genome scan identifies flowering-independent effects of barley HsDry2.2 locus on yield traits under water deficit

Increasing crop productivity under climate change requires the identification, selection and utilization of novel alleles for breeding. We analyzed the genotype and field phenotype of the barley HEB-25 multi-parent mapping population under well-watered and water-limited (WW and WL) environments for two years. A genome-wide association study (GWAS) for genotype by-environment interactions was performed for ten traits including flowering time (HEA), plant grain yield (PGY). Comparison of the GWAS for traits per-se to that for QTL-by-environment interactions (QxE), indicates the prevalence of QxE mostly for reproductive traits. One QxE locus on chromosome 2, Hordeum spontaneum Dry2.2 (HsDry2.2), showed a positive and conditional effect on PGY and grain number (GN). The wild allele significantly reduced HEA, however this earliness was not conditioned by water deficit. Furthermore, BC2F1 lines segregating for the HsDry2.2 showed the wild allele confers an advantage over the cultivated in PGY, GN and harvest index as well as modified shoot morphology, longer grain filling period and reduced senescence (only under drought), therefore suggesting adaptation mechanism against water deficit other than escape. This study highlights the value of evaluating wild relatives in search of novel alleles and clues to resilience mechanism underlying crop adaptation to abiotic stress.\n\nHighlightA flowering-time independent reproductive advantage of wild over cultivated allele under drought identified in a barley GWAS for genotype-by-environment interactions, with modified shoot morphology, reduced senescence and longer grain filling

genetics↗