Climate change conditions the selection of rust-resistant candidate wild lentil populations for in situ conservation

Cell Wall-Based Machine Learning Models to Predict Plant Growth Using Onion Epidermis

The plant cell wall (CW) is a physical barrier that plays a dual role in plant physiology, providing structural support for growth and development. Understanding the dynamics of CW growth is crucial for optimizing crop yields. In this study, we employed onion (Allium cepa L.) epidermis as a model system, leveraging its layered organization to investigate growth stages. Microscopic analysis revealed proportional variations in cell size in different epidermal layers, offering insights into growth dynamics and CW structural adaptations. Fourier transform infrared spectroscopy (FTIR) identified 11 distinct spectral intervals associated with CW components, highlighting structural modifications that influence wall elasticity and rigidity. Biochemical assays across developmental layers demonstrated variations in cellulose, soluble sugars, and antioxidant content, reflecting biochemical shifts during growth. The differential expression of ten cell wall enzyme (CWE) genes, analyzed via RT-qPCR, revealed significant correlations between gene expression patterns and CW composition changes across developmental layers. Notably, the gene expression levels of the pectin methylesterase and fucosidase enzymes were associated with the contents in cellulose, soluble sugar, and antioxidants. To complement these findings, machine learning models, including Support Vector Machines (SVM), k-Nearest Neighbors (kNN), and Neural Networks, were employed to integrate FTIR data, biochemical parameters, and CWE gene expression profiles. Our models achieved high accuracy in predicting growth stages. This underscores the intricate interplay among CW composition, CW enzymatic activity, and growth dynamics, providing a predictive framework with applications in enhancing crop productivity and sustainability.

The Prospects of gene introgression from crop wild relatives into cultivated lentil for climate change mitigation

Crop wild relatives (CWRs), landraces and exotic germplasm are important sources of genetic variability, alien alleles, and useful crop traits that can help mitigate a plethora of abiotic and biotic stresses and crop yield reduction arising due to global climatic changes. In the pulse crop genus Lens, the cultivated varieties have a narrow genetic base due to recurrent selections, genetic bottleneck and linkage drag. The collection and characterization of wild Lens germplasm resources have offered new avenues for the genetic improvement and development of stress-tolerant, climate-resilient lentil varieties with sustainable yield gains to meet future food and nutritional requirements. Most of the lentil breeding traits such as high-yield, adaptation to abiotic stresses and resistance to diseases are quantitative and require the identification of quantitative trait loci (QTLs) for marker assisted selection and breeding. Advances in genetic diversity studies, genome mapping and advanced high-throughput sequencing technologies have helped identify many stress-responsive adaptive genes, quantitative trait loci (QTLs) and other useful crop traits in the CWRs. The recent integration of genomics technologies with plant breeding has resulted in the generation of dense genomic linkage maps, massive global genotyping, large transcriptomic datasets, single nucleotide polymorphisms (SNPs), expressed sequence tags (ESTs) that have advanced lentil genomic research substantially and allowed for the identification of QTLs for marker-assisted selection (MAS) and breeding. Assembly of lentil and its wild species genomes (~4Gbp) opens up newer possibilities for understanding genomic architecture and evolution of this important legume crop. This review highlights the recent strides in the characterization of wild genetic resources for useful alleles, development of high-density genetic maps, high-resolution QTL mapping, genome-wide studies, MAS, genomic selections, new databases and genome assemblies in traditionally bred genus Lens for future crop improvement amidst the impending global climate change.

Identification and Characterization of Resistance to Rust in Lentil and Its Wild Relatives

Lentil rust is a major disease worldwide caused by Uromyces viciae-fabae. In this study, we screened a large germplasm collection of cultivated lentils (Lens culinaris ssp. culinaris) and its wild relatives, both in adult plants in the field with a local rust isolate during 2 seasons and in seedlings under controlled conditions with four fungal isolates of worldwide origin. The main results from our study were the following: (1) a significant number of accessions with resistance based on hypersensitive reaction (reduced Infection Type (IT)) were identified in cultivated lentil and in L. ervoides, L. nigricans and L.c. orientalis. The IT scores showed a clear isolate-specific response suggesting race-specificity, so each fungal isolate might be considered a different race. Resistance was identified against all isolates what might be the basis to develop a standard differential set that should be a priority for rust definition and monitoring. (2) Interestingly, although at lower frequency than in L. ervoides and L. nigricans, the hypersensitive response was also observed within cultivated lentil, with accession 1561 (L.c. culinaris) displaying resistance to the four isolates making this accession a valuable ready-to-use resource for lentil resistance breeding. Resistance to all other rust isolates was also available within L.c. culinaris in an isolate-specific manner. Accession 1308 (L. ervoides) showed resistance against all isolates tested, as well as a reduced number of accessions belonging to other wild Lens species. (3) In addition, our screenings allowed the identification of several accessions with partial resistance (reduced Disease Severity (DS) despite high IT). Adult Plant Resistance resulting in reduced severity in adult plants in the field, despite high susceptibility in seedlings, was more frequently identified in L.c. culinaris, but also in L. nigricans and L.c. orientalis.