Camalexin Production in Camelina sativa is Independent of Cotyledon Resistance to Sclerotinia sclerotiorum

Realizing the Potential of Camelina sativa as a Bioenergy Crop for a Changing Global Climate

Camelina sativa (L.) Crantz. is an annual oilseed crop within the Brassicaceae family. C. sativa has been grown since as early as 4000 BCE. In recent years, C. sativa received increased attention as a climate-resilient oilseed, seed meal, and biofuel (biodiesel and renewable or green diesel) crop. This renewed interest is reflected in the rapid rise in the number of peer-reviewed publications (>2300) containing “camelina” from 1997 to 2021. An overview of the origins of this ancient crop and its genetic diversity and its yield potential under hot and dry growing conditions is provided. The major biotic barriers that limit C. sativa production are summarized, including weed control, insect pests, and fungal, bacterial, and viral pathogens. Ecosystem services provided by C. sativa are also discussed. The profiles of seed oil and fatty acid composition and the many uses of seed meal and oil are discussed, including food, fodder, fuel, industrial, and medical benefits. Lastly, we outline strategies for improving this important and versatile crop to enhance its production globally in the face of a rapidly changing climate using molecular breeding, rhizosphere microbiota, genetic engineering, and genome editing approaches.

The causative agent of downy mildew Peronospora brassicae Gaeum. f. brassicae (Gaeum.) on winter false flax (Camelina sativa (L.) Crantz.): the search for a source of disease resistance in the conditions of the Krasnodar region

In recent years, in the conditions of the central zone of the Krasnodar region, downy mildew has become the most dangerous disease of winter false flax that affects the crop yield. Either the infected plants do not develop reproductive organs or these organs are undeveloped. The development of varieties resistant to infection by the disease causative agent allows efficient reducing the seed yield loss of winter false flax due to downy mildew without the use of chemical products. In 2015-2019, we conducted an assessment of the breeding material (528 cultivar samples) of winter false flax for resistance to downy mildew affection on a natural infection background. We determined that the causative agent of the disease is Peronospora brassicae Gaeum. f. brassicae (Gaeum.) Dzhan. We divided all cultivar samples into groups according to their resistance to the disease: immune, resistant, weakly resistant, weakly susceptible, susceptible. As a result of research, we selected 5 breeding samples (## 724, 726, 728, 730, 738) that were immune to downy mildew in the course of several years, with yield exceeding the standard variety Karat by 0.22-0.38 t/ha, and with oil content exceeding the standard by 0.2-0.5 %. We proposed to use the selected cultivar samples in the breeding process with the aim of developing new false flax varieties resistant to downy mildew.

Comparative Reaction of Camelina sativa to Sclerotinia sclerotiorum and Leptosphaeria maculans

Sclerotinia sclerotiorum and Leptosphaeria maculans are two of the most important pathogens of many cruciferous crops. The reaction of 30 genotypes of Camelina sativa (false flax) was determined against both pathogens. C. sativa genotypes were inoculated at seedling and adult stages with two pathotypes of S. sclerotiorum, highly virulent MBRS-1 and less virulent WW-1. There were significant differences (P < 0.001) among genotypes, between pathotypes, and a significant interaction between genotypes and pathotypes in relation to percent cotyledon disease index (% CDI) and stem lesion length. Genotypes 370 (% CDI 20.5, stem lesion length 1.8 cm) and 253 (% CDI 24.8, stem lesion length 1.4 cm) not only consistently exhibited cotyledon and stem resistance, in contrast to susceptible genotype 2305 (% CDI 37.7, stem lesion length 7.2 cm), but their resistance was independent to S. sclerotiorum pathotype. A F₅-recombinant inbred line population was developed from genotypes 370 × 2305 and responses characterized. Low broad-sense heritability indicated a complex pattern of inheritance of resistance to S. sclerotiorum. Six isolates of L. maculans, covering combinations of five different avirulent loci (i.e., five different races), were tested on C. sativa cotyledons across two experiments. There was a high level of resistance, with % CDI < 17, and including development of a hypersensitive reaction. This is the first report of variable reaction of C. sativa to different races of L. maculans and the first demonstrating comparative reactions of C. sativa to S. sclerotiorum and L. maculans. This study not only provides new understanding of these comparative resistances in C. sativa, but highlights their potential as new sources of resistance, both for crucifer disease-resistance breeding in general and to enable broader adoption of C. sativa as a more sustainable oilseed crop in its own right.