A Processible and Ultrahigh-temperature Organic Photothermal Material through Spontaneous and Quantitative [2+2] Cycloaddition-Cycloreversion.

Energy conversion, particularly light to heat conversion, has garnered significant attention owing to its prospect in renewable energy exploitation and utilization. Most previous efforts have focused on developing organic photothermal materials for low-temperature applications, whereas the importance of simplifying the preparation methods of photothermal materials and enhancing their maximum photothermal temperature have been less taken. Herein, we prepare an organic near-infrared (NIR) photothermal material namely ATT by a spontaneous [2+2] cycloaddition-cycloreversion reaction. In addition to the solution-based method, ATT could also be readily preapred by ball milling in a high yield of 90% in just 15 min. ATT powder exhibits a broad absorption extending beyond 2000 nm, excellent processability, and thermal stability. Remarkably, ATT powder can reach an unprecedently temperature as high as 450 °C while maintaining excellent photostability upon photoirradiation. Leveraging its extraordinary photothermal and processable properties, ATT was used in the high-temperature applications, such as photo-ignition, photo-controlled metal processing and high-temperature shape memory, all of which offer spatiotemporal control capabilities. This work provides a new approach to prepare organic photothermal materials with high temperatures, and pave the way for their applications in extreme environments.

Natural mating ability is associated with gut microbiota composition and function in captive male giant pandas.

The issue of poor sexual performance of some male giant pandas seriously impairs the growth and the genetic diversity of the captive population, yet there is still no clear understanding of the cause of the loss of this ability and its underlying mechanism. In this study, we analyzed the gut microbiota and its function in 72 fecal samples obtained from 20 captive male giant pandas, with an equal allocation between individuals capable and incapable of natural mating. Additionally, we investigated fecal hormone levels and behavioral differences between the two groups. A correlation analysis was then conducted among these factors to explore the influencing factors of their natural mating ability. The results showed significant differences in the composition of gut microbiota between the two groups of male pandas. The capable group had significantly higher abundance of Clostridium sensu stricto 1 (p adjusted = .0021, GLMM), which was positively correlated with fatty acid degradation and two-component system functions (Spearman, p adjusted < .05). Additionally, the capable group showed higher gene abundance in gut microbiota function including purine and pyrimidine metabolism and galactose metabolism, as well as pathways related to biological processes such as ribosome and homologous recombination (DEseq2, p adjusted < .05). We found no significant differences in fecal cortisol and testosterone levels between the two groups, and no difference was found in their behavior either. Our study provides a theoretical and practical basis for further studying the behavioral degradation mechanisms of giant pandas and other endangered mammal species.

Root-derived long-distance signals trigger ABA synthesis and enhance drought resistance in Arabidopsis.

Vascular plants have evolved intricate long-distance signaling mechanisms to cope with environmental stress, with reactive oxygen species (ROS) emerging as pivotal systemic signals in plant stress responses. However, the exact role of ROS as root-to-shoot signals in the drought response has not been determined. In this study, we reveal that compared with wild-type plants, ferric reductase defective 3 (frd3) mutants exhibit enhanced drought resistance concomitant with elevated NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) transcript levels and abscisic acid (ABA) contents in leaves as well as increased hydrogen peroxide (H2O2) levels in roots and leaves. Grafting experiments distinctly illustrate that drought resistance can be conferred by the frd3 rootstock regardless of the scion genotype, indicating that long-distance signals originating from frd3 roots promote an increase in ABA levels in leaves. Intriguingly, the drought resistance conferred by the frd3 mutant rootstock is weakened by the CAT2-overexpressing scion, suggesting that H2O2 may be involved in long-distance signaling. Moreover, the results of comparative transcriptome and proteome analyses support the drought resistance phenotype of the frd3 mutant. Taken together, our findings substantiate the notion that frd3 root-derived long-distance signals trigger ABA synthesis in leaves and enhance drought resistance, providing new evidence for root-to-shoot long-distance signaling in the drought response of plants.

Pyramiding of Low Chalkiness QTLs Is an Effective Way to Reduce Rice Chalkiness.

Rice chalkiness is a key limiting factor of high-quality rice. The breeding of low chalkiness varieties has always been a challenging task due to the complexity of chalkiness and its susceptibility to environmental factors. In previous studies, we identified six QTLs for the percentage of grain chalkiness (PGC), named qPGC5, qPGC6, qPGC8.1, qPGC8.2, qPGC9 and qPGC11, using single-segment substitution lines (SSSLs) with genetic background of Huajingxian 74 (HJX74). In this study, we utilized the six low chalkiness QTLs to develop 17 pyramiding lines with 2-4 QTLs. The results showed that the PGC decreased with the increase of QTLs in the pyramiding lines. The pyramiding lines with 4 QTLs significantly reduced the chalkiness of rice and reached the best quality level. Among the six QTLs, qPGC5 and qPGC6 showed greater additive effects and were classified as Group A, while the other four QTLs showed smaller additive effects and were classified as Group B. In pyramiding lines, although the presence of epistasis, additivity remained the main component of QTL effects. qPGC5 and qPGC6 showed stronger ability to reduce rice chalkiness, particularly in the environment of high temperature (HT) in the first cropping season (FCS). Our research demonstrates that by pyramiding low chalkiness QTLs, it is feasible to develop the high-quality rice varieties with low chalkiness at the best quality level even in the HT environment of FCS.

Giant panda (Ailuropoda melanoleuca) neonates use broadband calls to communicate with their mothers.

Infant call structure should have evolved to elicit maximum maternal attention and investment. Neonates of giant pandas produce three types of vocalizations reported to be vitally important in the context of mother-infant communications. However, how cubs, 0-15 days old, communicate with their mothers to elicit maternal care remains unknown. We analyzed 12 different call parameters of 3475 squawks, 1355 squalls, and 491 croaks from 11 captive giant panda (Ailuropoda melanoleuca) neonates from age 0 to 15 days. In playback experiments, we also tested whether mothers could detect ultrasound. Our results show that neonates use broadband calls with ultrasonic frequencies up to 65 kHz to convey information about their physiological needs and to attract maternal care. In playback experiments, we tested if mothers reacted differently to broadband calls (BBC) than to artificially altered calls that included only frequencies <20 kHz (AUDC) or calls that included only frequencies >20 kHz (USC). Playback confirmed that, although adult females responded significantly less often to USC, BBC than to or AUDC, they could detect USC, BBC and generally made appropriate behavioral responses, indicating a potential benefit for neonates to utilize ultrasonic and broadband frequencies. Our findings provide a new insight into mother-infant communication in giant pandas and will be helpful for reducing the mortality of cubs, younger than 1 month old, in captivity.

Single-nucleus transcriptome inventory of giant panda reveals cellular basis for fitness optimization under low metabolism.

BACKGROUND: Energy homeostasis is essential for the adaptation of animals to their environment and some wild animals keep low metabolism adaptive to their low-nutrient dietary supply. Giant panda is such a typical low-metabolic mammal exhibiting species specialization of extremely low daily energy expenditure. It has low levels of basal metabolic rate, thyroid hormone, and physical activities, whereas the cellular bases of its low metabolic adaptation remain rarely explored. RESULTS: In this study, we generate a single-nucleus transcriptome atlas of 21 organs/tissues from a female giant panda. We focused on the central metabolic organ (liver) and dissected cellular metabolic status by cross-species comparison. Adaptive expression mode (i.e., AMPK related) was prominently displayed in the hepatocyte of giant panda. In the highest energy-consuming organ, the heart, we found a possibly optimized utilization of fatty acid. Detailed cell subtype annotation of endothelial cells showed the uterine-specific deficiency of blood vascular subclasses, indicating a potential adaptation for a low reproductive energy expenditure. CONCLUSIONS: Our findings shed light on the possible cellular basis and transcriptomic regulatory clues for the low metabolism in giant pandas and helped to understand physiological adaptation response to nutrient stress.

qGLF5 from Oryza rufipogon Griff. improves kernel shape, plant architecture, and yield in rice.

KEY MESSAGE: A novel QTL qGLF5 from Oryza rufipogon Griff. improves yield per plant and plant architecture in rice. Kernel size and plant architecture are critical agronomic traits that are key targets for improving crop yield. From the single-segment substitution lines of Oryza rufipogon Griff. in the indica cultivar Huajingxian74 (HJX74) background, we identified a novel quantitative trait locus (QTL), named qGLF5, which improves kernel shape, plant architecture, and yield per plant in rice. Compared with the control HJX74, the plant height, panicles per plant, panicle length, primary branches per panicle, secondary branches per panicle, and kernels per plant of the near-isogenic line-qGLF5 (NIL-qGLF5) are significantly increased. NIL-qGLF5 has long and narrow kernels by regulating cell number, cell length and width in the spikelet hulls. Yield per plant of NIL-qGLF5 is increased by 35.02% compared with that of HJX74. In addition, qGLF5 significantly improves yield per plant and plant architecture of NIL-gw5 and NIL-GW7. These results indicate that qGLF5 might be beneficial for improving plant architecture and kernel yield in rice breeding by molecular design.

Substitution Mapping and Allelic Variations of the Domestication Genes from O. rufipogon and O. nivara.

BACKGROUND: Domestication from wild rice species to cultivated rice is a key milestone, which involved changes of many specific traits and the variations of the genetic systems. Among the AA-genome wild rice species, O. rufipogon and O. nivara, have many favorable genes and thought to be progenitors of O. sativa. RESULTS: In the present study, by using O. rufipogon and O. nivara as donors, the single segment substitution lines (SSSLs) have been developed in the background of the elite indica cultivar, HJX74. In the SSSLs population, 11 genes for 5 domestication traits, including tiller angle, spreading panicle, awn, seed shattering, and red pericarp, were identified and mapped on 5 chromosomes through substitution mapping. Herein, allelic variations of 7 genes were found through sequence alignment with the known genes, that is, TA7-RUF was allelic to PROG1, TA8-RUF was allelic to TIG1, SPR4-NIV was allelic to OsLG1, AN4-RUF was allelic to An-1, SH4-NIV was allelic to SH4, and both RC7-RUF and RC7-NIV were allelic to Rc. Meanwhile, 4 genes, TA11-NIV, SPR3-NIV, AN3-NIV, and AN4-NIV, were considered as the novel genes identified in these SSSLs, because of none known genes for the related domestication traits found in the chromosomal locations of them. CONCLUSION: The results indicated that the SSSLs would be precious germplasm resources for gene mining and utilization from wild rice species, and it laid the foundation for further analyses of the novel domestication genes to better understand the genetic basis in regulating the traits variation during domestication.

qGL3.4 controls kernel size and plant architecture in rice.

Kernel size and plant architecture play important roles in kernel yield in rice. Cloning and functional study of genes related to kernel size and plant architecture are of great significance for breeding high-yield rice. Using the single-segment substitution lines which developed with Oryza barthii as a donor parent and an elite indica cultivar Huajingxian74 (HJX74) as a recipient parent, we identified a novel QTL (quantitative trait locus), named qGL3.4, which controls kernel size and plant architecture. Compared with HJX74, the kernel length, kernel width, 1000-kernel weight, panicle length, kernels per plant, primary branches, yield per plant, and plant height of near isogenic line-qGL3.4 (NIL-qGL3.4) are increased, whereas the panicles per plant and secondary branches per panicle of NIL-qGL3.4 are comparable to those of HJX74. qGL3.4 was narrowed to a 239.18 kb interval on chromosome 3. Cell analysis showed that NIL-qGL3.4 controlled kernel size by regulating cell growth. qGL3.4 controls kernel size at least in part through regulating the transcription levels of EXPANSINS, GS3, GL3.1, PGL1, GL7, OsSPL13 and GS5. These results indicate that qGL3.4 might be beneficial for improving kernel yield and plant architecture in rice breeding.

GS6.1 controls kernel size and plant architecture in rice.

MAIN CONCLUSION: A novel QTL GS6.1 increases yield per plant by controlling kernel size, plant architecture, and kernel filling in rice. Kernel size and plant architecture are critical agronomic traits that greatly influence kernel yield in rice. Using the single-segment substitution lines (SSSLs) with an indica cultivar Huajingxian74 as a recipient parent and American Jasmine as a donor parent, we identified a novel quantitative trait locus (QTL), named GS6.1. Near isogenic line-GS6.1 (NIL-GS6.1) produces long and narrow kernels by regulating cell length and width in the spikelet hulls, thus increasing the 1000-kernel weight. Compared with the control, the plant height, panicles per plant, panicle length, kernels per plant, secondary branches per panicle, and yield per plant of NIL-GS6.1 are increased. In addition, GS6.1 regulates the kernel filling rate. GS6.1 controls kernel size by modulating the transcription levels of part of EXPANSINs, kernel filling-related genes, and kernel size-related genes. These results indicate that GS6.1 might be beneficial for improving kernel yield and plant architecture in rice breeding by molecular design.

Two complementary genes in a presence-absence variation contribute to indica-japonica reproductive isolation in rice.

Understanding the evolutionary forces in speciation is a central goal in evolutionary biology. Asian cultivated rice has two subspecies, indica and japonica, but the underlying mechanism of the partial reproductive isolation between them remains obscure. Here we show a presence-absence variation (PAV) at the Se locus functions as an indica-japonica reproductive barrier by causing hybrid sterility (HS) in indica-japonica crosses. The locus comprises two adjacent genes: ORF3 encodes a sporophytic pollen killer, whereas ORF4 protects pollen in a gametophytic manner. In F1 of indica-japonica crosses, pollen with the japonica haplotype, which lacks the sequence containing the protective ORF4, is aborted due to the pollen-killing effect of ORF3 from indica. Evolutionary analysis suggests ORF3 is a gene associated with the Asian cultivated rice species complex, and the PAV has contributed to the reproductive isolation between the two subspecies of Asian cultivated rice. Our analyses provide perspectives on rice inter-subspecies post-zygotic isolation, and will promote efforts to overcome reproductive barriers in indica-japonica hybrid rice breeding.

Click-Reaction-Mediated Chemotherapy and Photothermal Therapy Synergistically Inhibit Breast Cancer in Mice.

The development of functional materials for tumor immunogenicity enhancement is desirable for overcoming the low therapeutic efficiency and easy metastasis during tumor treatments. Herein, the thermoresponsive nanoparticles composed of photothermal agent (PTA) and click reactive reagent are developed for enhanced immunotherapy application. A Ni-bis(dithiolene)-containing PTA with intense near-infrared absorption and efficient photothermal conversion is developed for thermoresponsive nanoparticles construction. The generated heat by encapsulated PTA further induces the phase transition of thermoresponsive nanoparticles with the release of chemotherapy reagent to react with the amino groups on functional proteins, realizing PTT and chemotherapy simultaneously. Moreover, the immunogenic cell death (ICD) of cancer cells evoked by PTT could be further enhanced by the released reactive reagent. As a result, the synergistic effect of photothermal treatment and reaction-mediated chemotherapy can suppress the growth of a primary tumor, and the evoked ICD could further activate the immune response with the suppression of a distant tumor. This synergistic treatment strategy provides a reliable and promising approach for cancer immunotherapy in clinic.

PE-STOP: A versatile tool for installing nonsense substitutions amenable for precise reversion.

The rapid advances in genome editing technologies have revolutionized the study of gene functions in cell or animal models. The recent generation of double-stranded DNA cleavage-independent base editors has been suitably adapted for interrogation of protein-coding genes on the basis of introducing premature stop codons or disabling the start codons. However, such versions of stop/start codon-oriented genetic tools still present limitations on their versatility, base-level precision, and target specificity. Here, we exploit a newly developed prime editor (PE) that differs from base editors by its adoption of a reverse transcriptase activity, which enables incorporation of various types of precise edits templated by a specialized prime editing guide RNA. Based on such a versatile platform, we established a prime editing-empowered method (PE-STOP) for installation of nonsense substitutions, providing a complementary approach to the present gene-targeting tools. PE-STOP is bioinformatically predicted to feature substantially expanded coverage in the genome space. In practice, PE-STOP introduces stop codons with good efficiencies in human embryonic kidney 293T and N2a cells (with medians of 29% [ten sites] and 25% [four sites] editing efficiencies, respectively), while exhibiting minimal off-target effects and high on-target precision. Furthermore, given the fact that PE installs prime editing guide RNA-templated mutations, we introduce a unique strategy for precise genetic rescue of PE-STOP-dependent nonsense mutation via the same PE platform. Altogether, the present work demonstrates a versatile and specific tool for gene inactivation and for functional interrogation of nonsense mutations.

Grain shape is a factor affecting the stigma exsertion rate in rice.

Stigma exsertion rate (SER) is an index of outcrossing ability in rice and is a key trait of male sterile lines (MSLs) in hybrid rice. In this study, it was found that the maintainer lines carrying gs3 and gs3/gw8 showed higher SER. Single-segment substitution lines (SSSLs) carrying gs3, gw5, GW7 or gw8 genes for grain shape and gene pyramiding lines were used to reveal the relationship between grain shape and SER. The results showed that the grain shape regulatory genes had pleiotropic effects on SER. The SERs were affected by grain shapes including grain length, grain width and the ratio of length to width (RLW) not only in low SER background, but also in high SER background. The coefficients of determination (R2) between grain length and SER, grain width and SER, and grain RLW and SER were 0.78, 0.72, and 0.91 respectively. The grain RLW was the most important parameter affecting SER, and a larger grain RLW was beneficial to stigma exsertion. The pyramiding line PL-gs3/GW7/gw8 showed the largest grain RLW and the highest SER, which will be a fine breeding resource. Further research showed that the grain shape regulatory genes had pleiotropic effects on stigma shape, although the R2 values between grain shape and stigma shape, and stigma shape and SER were lower. Our results demonstrate that grain shape is a factor affecting SER in rice, in part by affecting stigma shape. This finding will be helpful for breeding MSLs with high SER in hybrid rice.

NIR luminogen for low-temperature photothermal therapy by triggering HSP90α down-regulation.

A near-infrared (NIR) luminogen TST was designed and used to efficiently trigger HSP90α protein knockdown through photo-thermal conversion based on a gene interference strategy, by which in vitro and in vivo tumor ablation were significantly acquired at low-temperature.

Development of a versatile nuclease prime editor with upgraded precision.

The applicability of nuclease-based form of prime editor (PEn) has been hindered by its complexed editing outcomes. A chemical inhibitor against DNA-PK, which mediates the nonhomologous end joining (NHEJ) pathway, was recently shown to promote precise insertions by PEn. Nevertheless, the intrinsic issues of specificity and toxicity for such a chemical approach necessitate development of alternative strategies. Here, we find that co-introduction of PEn and a NHEJ-restraining, 53BP1-inhibitory ubiquitin variant potently drives precise edits via mitigation of unintended edits, framing a high-activity editing platform (uPEn) apparently complementing the canonical PE. Further developments involve exploring the effective configuration of a homologous region-containing pegRNA (HR-pegRNA). Overall, uPEn can empower high-efficiency installation of insertions (38%), deletions (43%) and replacements (52%) in HEK293T cells. When compared with PE3/5max, uPEn demonstrates superior activities for typically refractory base substitutions, and for small-block edits. Collectively, this work establishes a highly efficient PE platform with broad application potential.

Fine Mapping of Two Major Quantitative Trait Loci for Rice Chalkiness With High Temperature-Enhanced Additive Effects.

Chalkiness is a crucial determinant of rice quality. During seed filling period, high temperature usually increases grain chalkiness, resulting in poor grain quality. Rice chalkiness was controlled by quantitative trait loci (QTLs) and influenced by environmental conditions. In this study, we identified two single-segment substitution lines (SSSLs) 22-05 and 15-06 with significantly lower percentage of grain chalkiness (PGC) than recipient Huajingxian 74 (HJX74) over 6 cropping seasons. Two major QTLs for chalkiness, qPGC5 and qPGC6, were located by substitution mapping of SSSLs 22-05 and 15-06, respectively. qPGC5 was located in the 876.5 kb interval of chromosome 5 and qPGC6 was located in the 269.1 kb interval of chromosome 6. Interestingly, the PGC of HJX74 was significantly different between the two cropping seasons per year, with 25.8% in the first cropping season (FCS) and 16.6% in the second cropping season (SCS), while the PGC of SSSLs 22-05 and 15-06 did not significantly differ between FCS and SCS. The additive effects of qPGC5 and qPGC6 on chalkiness in the SSSLs were significantly greater in FCS than in SCS. These results showed that qPGC5 and qPGC6 had major effects on chalkiness and the SSSL alleles were more effective in reducing chalkiness under high temperature condition in FCS. The fine-mapping of the two QTLs will facilitate the cloning of genes for chalkiness and provide new genetic resources to develop new cultivars with low chalkiness even under high temperature condition.

Reconstruction of the High Stigma Exsertion Rate Trait in Rice by Pyramiding Multiple QTLs.

Asian cultivated rice is a self-pollinating crop, which has already lost some traits of natural outcrossing in the process of domestication. However, male sterility lines (MSLs) need to have a strong outcrossing ability to produce hybrid seeds by outcrossing with restorer lines of male parents in hybrid rice seed production. Stigma exsertion rate (SER) is a trait related to outcrossing ability. Reconstruction of the high-SER trait is essential in the MSL breeding of rice. In previous studies, we detected eighteen quantitative trait loci (QTLs) for SER from Oryza sativa, Oryza glaberrima, and Oryza glumaepatula using single-segment substitution lines (SSSLs) in the genetic background of Huajingxian 74 (HJX74). In this study, eleven of the QTLs were used to develop pyramiding lines. A total of 29 pyramiding lines with 2-6 QTLs were developed from 10 SSSLs carrying QTLs for SER in the HJX74 genetic background. The results showed that the SER increased with increasing QTLs in the pyramiding lines. The SER in the lines with 5-6 QTLs was as high as wild rice with strong outcrossing ability. The epistasis of additive by additive interaction between QTLs in the pyramiding lines was less-than-additive or negative effect. One QTL, qSER3a-sat, showed minor-effect epistasis and increased higher SER than other QTLs in pyramiding lines. The detection of epistasis of QTLs on SER uncovered the genetic architecture of SER, which provides a basis for using these QTLs to improve SER levels in MSL breeding. The reconstruction of the high-SER trait will help to develop the MSLs with strong outcrossing ability in rice.

Development of Wide-Compatible Indica Lines by Pyramiding Multiple Neutral Alleles of Indica-Japonica Hybrid Sterility Loci.

Since the development of indica hybrid rice in the 1970s, great success has been achieved in hybrid rice production in China and around the world. The utilization of inter-subspecific indica-japonica hybrid rice has always been considered due to its stronger heterosis characteristics. However, indica-japonica hybrids face a serious problem of sterility, which hinders the exploitation of their heterosis. In the past decades, the genetic basis of indica-japonica hybrid sterility has been well studied. It was found that in sterile indica-japonica hybrids, female sterility was mainly controlled by the S5 locus and male sterility by the Sa, Sb, Sc, Sd, and Se loci. In this study, we developed wide-compatible indica lines (WCILs) by pyramiding multiple neutral (n) alleles of the hybrid sterility loci. First, we identified Sn alleles of the loci in single-segment substitution lines (SSSLs) in the genetic background of indica Huajingxian 74 (HJX74). Then, the Sn alleles of S5, Sb, Sc, Sd, and Se loci in SSSLs were pyramided in the HJX74 genetic background. The WCILs carrying Sn alleles at the S5, Sb, Sc, Sd, and Se loci showed wide compatibility with indica and japonica rice varieties. Therefore, the WCILs will be used to develop inter-subspecific indica-japonica hybrid rice with normal fertility.

Dynamic analysis of QTLs on plant height with single segment substitution lines in rice.

Dynamic regulation of QTLs remains mysterious. Single segment substitution lines (SSSLs) and conditional QTL mapping and functional QTL mappings are ideal materials and methods to explore dynamics of QTLs for complex traits. This paper analyzed the dynamics of QTLs on plant height with SSSLs in rice. Five SSSLs were verified with plant height QTLs first. All five QTLs had significant positive effects at one or more developmental stages except QTL1. They interacted each other, with negative effects before 49 d after transplanting and positive effects since then. The five QTLs selectively expressed in specific periods, mainly in the periods from 35 to 42 d and from 49 to 56 d after transplanting. Expressions of epistasis were dispersedly in various periods, negative effects appearing mainly before 35 d. The five QTLs brought the inflexion point ahead of schedule, accelerated growth and degradation, and changed the peak plant height, while their interactions had the opposite effects. The information will be helpful to understand the genetic mechanism for developmental traits.