Salinity has a significant impact on rice production in coastal, arid and semi-arid areas in many countries, including countries growing temperate rice, such as Kazakhstan. Recently, the complete genomes of 3000 rice accessions were sequenced through the 3 K rice genome project, and this set included 203 temperate japonica rice accessions. To identify salinity-tolerant germplasm and related genes for developing new salinity-tolerant breeding lines for the temperate japonica rice growing regions, we evaluated the seedling stage salinity tolerance of these sequenced temperate japonica rice accessions, and conducted genome-wide association studies (GWAS) for a series of salinity tolerance related traits. There were 27 accessions performed well (SES < 5.0) under moderate salinity stress (EC12), and 5 accessions were tolerant under both EC12 and EC18. A total of 26 QTLs were identified for 9 measured traits. Eleven of these QTLs were co-located with known salinity tolerance genes. QTL/gene clusters were observed on chromosome 1, 2, 3, 6, 8 and 9. Six candidate genes were identified for five promising QTLs. The alleles of major QTL Saltol and gene O S HKT1;5 (SKC1) for Na+/K+ ratio identified in indica rice accessions were different from those in the temperate japonica rice accessions used in this study. Salinity tolerant temperate japonica rice accessions were identified in this study, these accessions are important resources for breeding programs. SNPs located in the promising QTLs and candidate genes could be used for future gene validation and marker assisted selection. This study provided useful information for future studies on genetics and breeding of salinity tolerance in temperate japonica rice.

The domain of unknown function 560 (DUF560), also known as the PDDEXK_6 family, is a ubiquitous plant protein that has been confirmed to play critical roles in Arabidopsis root development as well as ABA and abiotic responses. However, genome-wide identification and expression pattern analysis in rice (Oryza sativa) still need to be improved. Based on the phylogenetic relationship, 10 OsDUF506 genes were identified and classified into four subfamilies. Segmental duplication was essential to the expansion of OsDUF506s, which were subjected to purifying selective pressure. Except for OsDUF50609 and OsDUF50610, the OsDUF506s shared colinear gene pairs with five monocot species, showing that they were conserved in evolution. Furthermore, the conserved domains, gene structures, SNPs distribution, and targeting miRNAs were systematically investigated. Massive cis-regulatory elements were discovered in promoter regions, implying that OsDUF506s may be important in hormone regulation and abiotic stress response. Therefore, we analyzed plant hormone-induced transcriptome data and performed qRT-PCR on eight OsDUF506s under drought, cold, and phosphorus-deficient stresses. The results revealed that most OsDUF506s respond to ABA and JA treatment, as well as drought and cold conditions. In conclusion, our findings provided insights into the evolution and function of OsDUF506s, which could benefit crop breeding in the future.

Temperate japonica rice plays a very important role in food security. In this study, a set of 191 temperate japonica accessions from 30 countries were planted in two sites in China, and 12 agronomic traits were measured. The results showed a wide range of variation for the traits measured. Most of the accessions are short; three accessions with large panicles and seven accessions with large grains were identified. Sixty-two quantitative trait loci (QTLs) were identified for 12 traits that were measured. Among them, twenty-one QTLs were identified in both experiments, and 41 QTLs were identified in only one site. Some known genes are located in the QTL regions identified in our study. SNP markers for grain size were identified and could be efficiently used for breeding selection. This study provided useful information for future gene validation and marker assisted selection for some important agronomic traits of temperate japonica rice.

Strains from the genus of Pectobacterium can cause soft rot in numerous important plants, leading to significant losses. 16S rRNA gene sequences reliably identify genera, but species identification is sometimes challenging due to indistinguishable species or strains and unrecognized new taxa. Therefore, a dependable and straightforward classification method is needed. In this study, we analyzed the complete genome sequence and predicted genome components of Pectobacterium strains. We also assessed their genetic relationships using average nucleotide identity and in silico DNA–DNA hybridization, alongside phylogenetic analysis. This was done by examining the whole-genome sequences of 14 new strains isolated in our laboratory, responsible for plant soft rot, and comparing them with 64 strains’ genome sequences available in GenBank. The results reveal that three subspecies of P. carotovorum with genome sequences deposited in GenBank (PccS1, PCC21, and strain 67) need to be reclassified as separate species and also confirm that our new isolated strains are accurately categorized at the species level. Additionally, the virulence and adaptability of certain strains of Pectobacterium (PccS1, SCRI1043, and SCC3193) are influenced by horizontal acquisition genes. Furthermore, our findings suggest that the diversity in the car gene cluster among Pectobacterium strains likely stems from gene losing, as well as the auto-induced regulatory mechanisms underlying virulence determinant gene activation, and Car biosynthesis might act in different ways in PccS1, enhancing our knowledge of their genomic traits through comparative studies.

Two-line hybrid rice breeding relies on photoperiod-/thermosensitive genic male sterile (P/TGMS) lines with reliable fertility transition across different environments. The fertility of japonica P/TGMS lines is intricately regulated by photoperiod and temperature, making it more challenging to breed japonica sterile lines with stable sterility than indica sterile lines. This complexity is one of the primary reasons the breeding and promotion of two-line japonica hybrid rice has lagged behind that of indica hybrid rice. Here, we report on Yun1032S, a novel japonica P/TGMS line bred in the low-latitude plateau. It was bred by crossing Peiai 64S, the famous P/TGMS line with the largest application area in China, with Yungengyou 1, a plateau japonica variety noted for its excellent cold tolerance and disease resistance. Yun1032S exhibited stable sterility and female-parent traits favorable for two-line seed production. The elite combination YLY7706 (Yunliangyou7706), derived from a cross between Yun1032S and Yungenghui7501, showed a stable and competitive yield and strong disease resistance in the 2022–2023 Yunnan provincial regional trials. To analyze the genetic basis of phenotypes, we performed whole-genome resequencing and functional loci analysis of the parents and found that they carry a great number of superior alleles, which account for their yield and disease-resistant performance. To assess the breeding value of Yun1032S, we analyzed heterosis of a new batch of combinations derived from Yun1032S and identified a new combination, Jian3, with greater yield potential than YLY7706. These findings not only enhance the breeding of japonica P/TGMS lines but also provide direction for future pairing of two-line hybrid combination breeding. The study presents innovative concepts that further integrate genomics with traditional breeding techniques. Ultimately, Yun1032S marks a significant milestone in japonica P/TGMS line breeding technology, opening new avenues for the development of the two-line system.

Fertilizer management plays a critical role in regulating both yield and aroma quality in fragrant rice. However, the combined effects of functional fertilizers on these traits across different varieties and ecological conditions remain poorly understood. In this study, field experiments were conducted at two sites (Fumin and Dali) using two japonica fragrant rice varieties (Yunjing 37 and Liuxiangzi 1) under four fertilization treatments: T1 (conventional fertilization); T2 (compound fertilizer + silicon fertilizer); T3 (compound fertilizer + magnesium ammonium phosphate + amino acid-chelated calcium); and T4 (compound fertilizer + bio-organic fertilizer + zinc + amino acid water-soluble fertilizer). Compared with T1, silicon application (T2) significantly increased grain yield by 8.58–15.08%, primarily through synergistic increases in effective panicles and grains per panicle. Treatments T3 and T4 significantly enhanced grain 2-acetyl-1-pyrroline (2-AP) content by 18.32–32.67% and increased the diversity of volatile compounds. Correlation analysis revealed that 2-AP content was positively correlated with ketones (r = 0.373, p < 0.05) and alcohols (r = 0.363, p < 0.05), and negatively correlated with aldehydes and esters. Multifactor ANOVA showed no significant variety × treatment interaction for yield or 2-AP content (p > 0.05), indicating consistent responses across varieties. These results provide preliminary evidence that silicon fertilizer serves as an effective strategy for yield improvement, while combined application of calcium, magnesium, and amino acids enhances aroma quality by promoting the accumulation of 2-APm ketones, and alcohols. However, because treatments T3 and T4 contained multiple components, the individual contributions of Ca, Mg, or amino acids cannot be isolated. Multi-year trials are required to confirm the stability of these effects, featuring a differentiated fertilization strategy—silicon for yield and medium/trace elements for aroma—applicable across varieties, with site-specific variety selection further optimizing performance.