With global warming, plant high temperature injury is becoming an increasingly serious problem. In wheat, barley, and various other commercially important crops, the early phase of anther development is especially susceptible to high temperatures. Activation of auxin biosynthesis with increased temperatures has been reported in certain plant tissues. In contrast, we here found that under high temperature conditions, endogenous auxin levels specifically decreased in the developing anthers of barley and Arabidopsis . In addition, expression of the YUCCA auxin biosynthesis genes was repressed by increasing temperatures. Application of auxin completely reversed male sterility in both plant species. These findings suggest that tissue-specific auxin reduction is the primary cause of high temperature injury, which leads to the abortion of pollen development. Thus, the application of auxin may help sustain steady yields of crops despite future climate change.

Although muscle atrophy is a serious problem during spaceflight, little is known about the sequence of molecular events leading to atrophy in response to microgravity. We carried out a spaceflight experiment using Caenorhabditis elegans onboard the Japanese Experiment Module of the International Space Station. Worms were synchronously cultured in liquid media with bacterial food for 4 days under microgravity or on a 1-G centrifuge. Worms were visually observed for health and movement and then frozen. Upon return, we analyzed global gene and protein expression using DNA microarrays and mass spectrometry. Body length and fat accumulation were also analyzed. We found that in worms grown from the L1 larval stage to adulthood under microgravity, both gene and protein expression levels for muscular thick filaments, cytoskeletal elements, and mitochondrial metabolic enzymes decreased relative to parallel cultures on the 1-G centrifuge (95% confidence interval (P⩽0.05)). In addition, altered movement and decreased body length and fat accumulation were observed in the microgravity-cultured worms relative to the 1-G cultured worms. These results suggest protein expression changes that may account for the progressive muscular atrophy observed in astronauts.

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p97 (CDC-48 inCaenorhabditis elegans) is a ubiquitin-selective AAA (ATPases associated with diverse cellular activities) chaperone and its key function is to disassemble protein complexes. p97 functions in diverse cellular processes including endoplasmic reticulum (ER)-associated degradation, membrane fusion, and meiotic and mitotic progression. However, its cellular functions in development have not yet been clarified. Here, we present data that p97 is involved in the switch from spermatogenesis to oogenesis in the germline of the C. elegans hermaphrodite. We found that the cdc-48.1 deletion mutant produced less sperm than the wild type and thus showed a decreased brood size. The cdc-48.1 mutation suppressed the sperm-overproducing phenotypes of fbf-1 and fem-3(gf) mutants. In addition, the p97/CDC-48-UFD-1-NPL-4 complex interacted with the E3 ubiquitin ligase CUL-2 complex via NPL-4 binding to Elongin C. Furthermore, TRA-1A, which is the terminal effector of the sex determination pathway and is regulated by CUL-2-mediated proteolysis, accumulated in the cdc-48.1 mutant. Proteasome activity was also required for the brood size determination and sperm-oocyte switch. Our results demonstrate that the C. elegans p97/CDC-48-UFD-1-NPL-4 complex controls the sperm-oocyte switch by regulating CUL-2-mediated TRA-1A proteasome degradation.

Background: The primer RNA for the synthesis of the minus strand of filamentous coliphages is produced by host RNA polymerase at a specific site on the plus strand template. The mechanism used by the enzyme in recognizing the origin is unknown, but minus strand replication requires the holoenzyme form of RNA polymerase. The origin contains two inverted repeats which can form hairpins.