Cyanogenesis in the Sorghum Genus: From Genotype to Phenotype

Domestication has resulted in a loss of genetic diversity in our major food crops, leading to susceptibility to biotic and abiotic stresses linked with climate change. Crop wild relatives (CWR) may provide a source of novel genes potentially important for re-gaining climate resilience. Sorghum bicolor is an important cereal crop with wild relatives that are endemic to Australia. Sorghum bicolor is cyanogenic, but the cyanogenic status of wild Sorghum species is not well known. In this study, leaves of wild species endemic in Australia are screened for the presence of the cyanogenic glucoside dhurrin. The direct measurement of dhurrin content and the potential for dhurrin-derived HCN release (HCNp) showed that all the tested Australian wild species were essentially phenotypically acyanogenic. The unexpected low dhurrin content may reflect the variable and generally nutrient-poor environments in which they are growing in nature. Genome sequencing of six CWR and PCR amplification of the CYP79A1 gene from additional species showed that a high conservation of key amino acids is required for correct protein function and dhurrin synthesis, pointing to the transcriptional regulation of the cyanogenic phenotype in wild sorghum as previously shown in elite sorghum.

Novel Centromeric and Subtelomeric Repetitive DNA Sequences for Karyotyping the Bambara Groundnut (Vigna subterranea L. Verdc.)

Bambara groundnut (<i>Vigna subterranea</i> L. Verdc.) is an un­derutilized minor legume crop with climate resilience and great potential use in world agriculture. This study aimed to cytogenetically characterize the genome and chromosome properties of Bambara groundnut. We cloned, sequenced, and mapped a 50-bp centromere-specific tandem repeat on all chromosomes. In addition, a 400-bp subtelomeric repeat was discovered and mapped on a single pair of chromosomes. A Bambara groundnut karyotype was constructed using these novel repeats along with ribosomal RNA genes (45S and 5S) and telomeric DNA sequences. This study provides the first analysis of the genome and chromosome properties of Bambara groundnut. We discuss our findings in relation to genetic improvement of Bambara groundnut and centromere evolution in legume species.

The Future of Climate Resilience in Wheat

As the most widely cultivated crop globally - providing 20% of all human calories and protein - there is an urgent need to increase wheat’s resilience to harsher climates [1]. The risk of simultaneous crop failures due to heat and/or drought in global “breadbaskets” has risen and is projected to rise further [2-4]. Severe water scarcity events are predicted for up to 60% of the world’s wheat-growing areas by the end of this century [5]. Furthermore, for each 1°C increase in average seasonal temperature, it is predicted that wheat yields will decrease by 6% on average globally, and much more in some already marginal environments where wheat is a traditional staple food [6,7]. At the current rate of yield gain, wheat production is predicted to fall well short of future demand due to population growth alone. Emerging environmental threats only make the challenge harder. On top of this, demand by consumers, farmers and the food industry is predicted to increase due to wheat’s high grain-protein content relative to other cereals, wide growing range and adaptability to most environmental stresses. Since farmer adoption of improved cultivars is a critical part of adaptation [8], new and more targeted breeding efforts are needed to ensure that wheat's climate resilience is maximized [9-11]. This article briefly outlines research that has been conducted and current research needs to develop climate resilient wheat.

Towards transboundary networks of climate-smart marine reserves in the Southern California Bight

Climate-smart conservation addresses the vulnerability of biodiversity to climate change impacts but may require transboundary considerations. Here, we adapt and refine 16 biophysical guidelines for climate-smart marine reserves for the transboundary California Bight ecoregion. We link several climate-adaptation strategies (e.g., maintaining connectivity, representing climate refugia, and forecasting effectiveness of protection) by focusing on kelp forests and associated species. We quantify transboundary larval connectivity along ~800 km of coast and find that the number of connections and the average density of larvae dispersing through the network under future climate scenarios could decrease by ~50%, highlighting the need to protect critical steppingstone nodes. We also find that although focal species will generally recover with 30% protection, marine heatwaves could hinder subsequent recovery in the following 50 years, suggesting that protecting climate refugia and expanding the coverage of marine reserves is a priority. Together, these findings provide a first comprehensive framework for integrating climate resilience for networks of marine reserves and highlight the need for a coordinated approach in the California Bight ecoregion.

A polycentric food sovereignty approach to climate resilience in the Philippines

Enhancing climate resilience in agrarian communities requires improving the underlying socioecological conditions for farmers to engage in adaptation and mitigation strategies, alongside collaborative and redistributive community development to reduce vulnerabilities. To overcome barriers to climate resilience in the Philippines, a grassroots farmer-led organization comprised of resource-poor smallholders, scientists, and nongovernmental organizations have organized a polycentric network over the past 30 years to implement food sovereignty initiatives. We explore the extent to which the network’s decentralized and farmer-led organizational structure; programming and services; promotion of diversified, organic, and agroecological farming systems; and political organizing and advocacy create broadly accessible and diverse pathways for resource-poor smallholders to build climate resilience. We find that the Magsasaka at Siyentipiko para sa Pag-Unlad ng Agrikultura’s (Farmer-Scientist Partnership for Development) polycentric governance approach directly addresses the root causes of vulnerability, particularly in working to reclaim farmer rights and control over resources, connecting local and global struggles, and revitalizing agrobiodiversity and place-based knowledge.

Enhancing climate resilience using stress-tolerant maize in conservation agriculture in southern Africa.

Recurrent and widespread droughts in southern Africa (SA) reduce agricultural productivity and increase food insecurity among smallholder farmers. The average growing-season temperatures are expected to increase by 2.5°C. In SA maize is a staple food, accounting for more than 30% of total calories. The crop is mostly grown by smallholder farmers with limited inputs of fertilizers and improved seed. Most of the maize cultivars grown by farmers are susceptible to heat and drought. Multi-stress-tolerant maize germplasm is one of the climate smart agriculture (CSA) components and, when used in combination with others, can sustainably increase production and resilience of agricultural systems. In this paper we review the performance and economic benefits of drought-tolerant maize cultivars under conventional monocropping practice, under conventional intercropping and in Conservation Agriculture (CA) as part of sustainable intensification to ensure food security for smallholder farmers.