Russian, US, Chinese hypersonic arms lack treaty curbs

Significance Soon after Biden's inauguration as president tomorrow, US and Russian diplomats are expected to discuss an extension to New START, the only remaining major agreement regulating their nuclear forces. This can be done quickly; the main outstanding question is whether to prolong it for the maximum five years permitted or settle on a shorter extension. Impacts With New START renewed, Washington and Moscow will seek clarity on next steps in nuclear threat reduction and arms control. This could be a lengthy process, requiring internal reviews of nuclear policy, force posture, arms control and bilateral relations. The alternative is an increase in mutual suspicions of force plans, further erosion of trust and pressure to enlarge nuclear budgets. COVID-19 management will consume government attention to and budgets for defence and diplomacy.

Significance The likely end of the Intermediate-Range Nuclear Forces (INF) treaty will be an important marker in the decline of international stability and a particular blow to long-held assumptions about European security. It comes at a time when US-Russian dialogue has stalled and uncertainties about intentions and evolving technologies abound. Impacts The INF issue will feed Moscow's narrative about encirclement by hostile forces. Despite delays to arms programmes, Russia has proved adept at developing and adapting smaller missile types. President Donald Trump is unlikely to engage meaningfully with Russia on the detail of arms control.

Subject Prospects for nuclear arms control in 2019-23. Significance Russia and the United States have reached an apparent impasse on nuclear weapons. Presidents Donald Trump and Vladimir Putin warn of the dangers of a new nuclear arms race, but neither appears ready to make the concessions necessary to salvage the current arms control and non-proliferation regime. Attending a NATO foreign ministers' meeting yesterday, US Secretary of State Mike Pompeo set a 60-day deadline for Russia to comply with the Intermediate-Range Nuclear Forces (INF) treaty.

The rise of “the rest,” especially China, has triggered an inevitable transformation of the so-called liberal international order. Rising powers have started to both challenge and push for the reform of existing multilateral institutions, such as the International Monetary Fund (IMF), and to create new ones, such as the Asian Infrastructure Investment Bank (AIIB). The United States under the Trump administration, on the other hand, has retreated from the international institutions that the country once led or helped to create, including the Trans-Pacific Partnership (TPP); the Paris Agreement; the Iran nuclear deal; the Intermediate-Range Nuclear Forces (INF) Treaty; the United Nations Educational, Scientific and Cultural Organization (UNESCO); and the United Nations Human Rights Council (UNHRC). The United States has also paralyzed the ability of the World Trade Organization (WTO) to settle trade disputes by blocking the appointment of judges to its appellate body. Moreover, in May 2020, President Trump announced his decision to quit the Open Skies Treaty, an arms control regime designed to promote transparency among its members regarding military activities. During the past decade or so, both Russia and the United States have been dismantling multilateral arms control treaties one by one while engaging in new nuclear buildups at home.

ABSTRACT Plants deploy cell surface receptors known as pattern-recognition receptors (PRRs) that recognize non-self molecules from pathogens and microbes to defend against invaders. PRRs typically recognize microbe-associated molecular patterns (MAMPs) that are usually widely conserved, some even across kingdoms. Here, we report an oomycete-specific family of small secreted cysteine-rich (SCR) proteins that displays divergent patterns of sequence variation in the Irish potato famine pathogen Phytophthora infestans. A subclass that includes the conserved effector PcF from Phytophthora cactorum activates immunity in a wide range of plant species. In contrast, the more diverse SCR74 subclass is specific to P. infestans and tends to trigger immune responses only in a limited number of wild potato genotypes. The SCR74 response was recently mapped to a G-type lectin receptor kinase (G-LecRK) locus in the wild potato Solanum microdontum subsp. gigantophyllum. The G-LecRK locus displays a high diversity in Solanum host species compared to other solanaceous plants. We propose that the diversification of the SCR74 proteins in P. infestans is driven by a fast coevolutionary arms race with cell surface immune receptors in wild potato, which contrasts the presumed slower dynamics between conserved apoplastic effectors and PRRs. Understanding the molecular determinants of plant immune responses to these divergent molecular patterns in oomycetes is expected to contribute to deploying multiple layers of disease resistance in crop plants. IMPORTANCE Immune receptors at the plant cell surface can recognize invading microbes. The perceived microbial molecules are typically widely conserved and therefore the matching surface receptors can detect a broad spectrum of pathogens. Here we describe a family of Phytophthora small extracellular proteins that consists of conserved subfamilies that are widely recognized by solanaceous plants. Remarkably, one subclass of SCR74 proteins is highly diverse, restricted to the late blight pathogen Phytophthora infestans and is specifically detected in wild potato plants. The diversification of this subfamily exhibits signatures of a coevolutionary arms race with surface receptors in potato. Insights into the molecular interaction between these potato-specific receptors and the recognized Phytophthora proteins are expected to contribute to disease resistance breeding in potato.