Vinous-throated parrotbills breed in invasive smooth cordgrass habitat:Can native birds avoid the potential ecological trap?

Native animals are facing long-term coexistence with invasive plants worldwide,the impacts of which on animal behavior remain poorly known.Potential ecological traps could threaten native birds breeding in invasive plant habitats,but behavioral strategies for birds to avoid such risks are few concerned.The invasion of Smooth Cordgrass(Spartina alterniflra) has seriously varied the vegetation landscape in the coastal wetlands of eastern China,and affected the habitat selection of native birds.Here,we investigated the nesting and breeding characteristics of a common native passerine,the Vinous-throated Parrotbill(Sinosuthora webbiana),in habitats dominated by native Common Reed(Phragmites australis) and exotic cordgrass.We found that parrotbills could complete their breeding cycle in cordgrass habitat.Most nest failure was attributed to predation in native habitat but tide inundation in cordgrass habitat.However,the nest success rate and daily survival rate(DSR) in cordgrass habitat were higher.Moreover,nest height was markedly higher in cordgrass habitat and was the most important influencing variable(positively correlated with the DSR).These results suggest that cordgrass habitat is a potential ecological trap due to the tide inundation,but some parrotbills seem to effectively avoid this risk by increasing nest height.Our study reveals that a native passerine changes its nesting behavior to accommodate invasive plant habitat and highlights that habitat changes caused by invasive plants may drive the adaptive evolution of native animal behavior.The limitation of these results must be acknowledged for the small sample size,and there is a need for a larger sample and long-term data for further verification.

Loss-of-function mutation of rice SLAC7 decreases chloroplast stability and induces a photoprotection mechanism in rice

Plants absorb sunlight to power the photochem- ical reactions of photosynthesis, which can potentially damage the photosynthetic machinery. However, the mech- anism that protects chloroplasts from the damage remains unclear. In this work, we demonstrated that rice （Oryza sativa L.） SLAC7 is a generally expressed membrane protein. Loss- of-function of SLAC7 caused continuous damage to the chloroplasts of mutant leaves under normal light conditions. Ion leakage indicators related to leaf damage such as H^O2 and abscisic acid levels were significantly higher in slac7-1 than in the wild type. Consistently, the photosynthesis efficiency and Fv/Fm ratio of slac7-1 were significantly decreased （similar to photoinhibition）. In response to chloroplast damage, slat7- 1 altered its leaf morphology （curled or fused leaf） by the synergy between plant hormones and transcriptional factors to decrease the absorption of light, suggesting that a photoprotection mechanism for chloroplast damage was activated in slac7-1. When grown in dark conditions, slac7-1 displayed a normal phenotype. 5LAC7 under the control of the AtSLAC1 promoter could partially complement thephenotypes of Arabidopsis slacl mutants, indicating a partial conservation of SLAC protein functions. These results suggest that SLAC7 is essential for maintaining the chloroplast stability in rice.

The calcium-dependent kinase OsCPK24 functions in cold stress responses in rice

Calcium-dependent protein kinases（CPKs）are serine/threonine protein kinases that function in plant stress responses. Although CPKs are recognized as key messengers in signal transduction, the specific roles of CPKs and the molecular mechanisms underlying their activity remain largely unknown. Here, we characterized the function of Os CPK_（24）, a cytosol-localized calciumdependent protein kinase in rice. Os CPK_（24） was universally and highly expressed in rice plants and was induced by cold treatment. Whereas Os CPK_（24） knockdown plants exhibited increased sensitivity to cold compared to wild type（WT）, Os CPK_（24）-overexpressing plants exhibited increased cold tolerance. Plants overexpressing Os CPK_（24） exhibited increased accumulation of proline（an osmoprotectant） and glutathione（an antioxidant） and maintained a higher GSH/GSSG（reduced glutathione to oxidized glutathione） ratio during cold stress compared to WT. In addition to these effects in response to cold stress, we observed the kinase activity of Os CPK_（24） varied under different calcium concentrations. Further,Os CPK_（24） phosphorylated Os Grx_（10）, a glutathionedependent thioltransferase, at rates modulated by changes in calcium concentration. Together, our results support the hypothesis that Os CPK_（24） functions as a positive regulator of cold stress tolerance in rice, a process mediated by calcium signaling and involving phosphorylation and the inhibition of Os Grx_（10） to sustain higher glutathione levels.

Song variation of a native songbird in a modified habitat by invasive plant

Habitat structure has been considered as an important factor affecting the acoustic evolution of birds,and bird songs are increasingly affected by artificial environmental variation.Invasive plants sometimes can dramatically alter native habitats,but the song variation of native songbirds migrating into invaded habitats has received little attention.The invasion of smooth cordgrass Spartina alterniflora in the coastal wetlands of eastern China has drastically altered the vegetation structure and some small passerines have begun to use invaded habitats to breed.In this study,we compared the song type prevalence and the song characteristics of male plain prinia Prinia inornata to identify differences in vocal behavior between native and invaded habitats.We also tested for differences in vocal behavior in relation to singing perch and wind speed variation between different habitats.The results indicated that males of plain prinia in invaded habitats sang shorter songs than those in native habitats and had a lower song diversity.The homogeneous vegetation structure and higher wind speed in invaded habitats likely leads to males changing the traditional perched singing style.The song variation may be related to the founder effect,the alteration of vegetation structure and microclimate in invaded habitats.This finding highlights the need for better understanding the behavioral evolution of native species in the process of adapting to the invaded habitat.In the future,experimental manipulation is needed to ascertain how the invasive plant drove these vocal behavior changes of native songbirds.