Summary: Global warming has reduced the productivity of many field‐grown crops, as the effects of high temperatures can lead to male sterility in such plants. Genetic regulation of the high temperature (HT) response in the major crop cotton is poorly understood. We determined the functionality and transcriptomes of the anthers of 218 cotton accessions grown under HT stress. By analyzing transcriptome divergence and implementing a genome‐wide association study (GWAS), we identified three thermal tolerance associated loci which contained 75 protein coding genes and 27 long noncoding RNAs, and provided expression quantitative trait loci (eQTLs) for 13 132 transcripts. A transcriptome‐wide association study (TWAS) confirmed six causal elements for the HT response (three genes overlapped with the GWAS results) which are involved in protein kinase activity. The most susceptible gene, GhHRK1, was confirmed to be a previously uncharacterized negative regulator of the HT response in both cotton and Arabidopsis. These functional variants provide a new understanding of the genetic basis for HT tolerance in male reproductive organs.

Use of Plantago ovata Forsk leaf (also known as blond plantain or isabgol) extract is a novel approach for ameliorating water stress in various agronomic crops such as maize (Zea mays L.). To examine the potential roles of P. ovata extract (0, 20 and 40%) in increasing seed germination, plant growth, photosynthetic measurements, stomatal properties, oxidative stress and antioxidant response, ions uptake and the relationship between studied parameters, we investigated the impacts of its short-term seed priming on Z. mays L. elite cultivar “Cimmyt-Pak” under a control environment and a water deficit stress environment (induced by PEG). It was evident that water deficit stress conditions induced a negative impact on plant growth, stomatal properties and ion uptake in different organs of Z. mays. The decrease in growth-related attributes might be due to overproduction of oxidative stress biomarkers, i.e., malondialdehyde (MDA) contents, hydrogen peroxide (H₂O₂) initiation, and electrolyte leakage (%), which was also overcome by the enzymatic antioxidants, i.e., superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants, which increased under the water stress environment. However, seed priming with P. ovata extract positively increased germination rate and growth profile, and protected photosynthetic apparatus and stomatal properties by decreasing oxidative stress indicators and increasing activities of antioxidant compounds. Our results also depicted that the optimum concentration of P. ovata extract for Z. mays seedlings under water stress conditions was 20%, while a further increase in P. ovata extract (40%) induced a non-significant negative impact on growth and biomass of Z. mays seedling. In addition, the effect was more promising on Z. mays seedlings when grown under controlled conditions. Here, we concluded that the understanding of the role of seed priming with P. ovata extract in the increment of growth-related attributes, photosynthetic apparatus (Pn, Gs, Ts and Ci) and nutrient uptake (Ca²⁺, Fe²⁺, P and Mg²⁺) introduces new possibilities for their effective use in water deficit stress environments and shows a promising foundation for Z. mays tolerance against water deficit stress conditions.

Tetraploid Robinia pseudoacacia L. is a difficult-to-root species, and is vegetatively propagated through stem cuttings. Limited information is available regarding the adventitious root (AR) formation of dark-pretreated micro-shoot cuttings. Moreover, the role of specific miRNAs and their targeted genes during dark-pretreated AR formation under in vitro conditions has never been revealed. The dark pretreatment has successfully promoted and stimulated adventitious rooting signaling-related genes in tissue-cultured stem cuttings with the application of auxin (0.2 mg L⁻¹ IBA). Histological analysis was performed for AR formation at 0, 12, 36, 48, and 72 h after excision (HAE) of the cuttings. The first histological events were observed at 36 HAE in the dark-pretreated cuttings; however, no cellular activities were observed in the control cuttings. In addition, the present study aimed to uncover the role of differentially expressed (DE) microRNAs (miRNAs) and their targeted genes during adventitious root formation using the lower portion (1–1.5 cm) of tetraploid R. pseudoacacia L. micro-shoot cuttings. The samples were analyzed using Illumina high-throughput sequencing technology for the identification of miRNAs at the mentioned time points. Seven DE miRNA libraries were constructed and sequenced. The DE number of 81, 162, 153, 154, 41, 9, and 77 miRNAs were upregulated, whereas 67, 98, 84, 116, 19, 16, and 93 miRNAs were downregulated in the following comparisons of the libraries: 0-vs-12, 0-vs-36, 0-vs-48, 0-vs-72, 12-vs-36, 36-vs-48, and 48-vs-72, respectively. Furthermore, we depicted an association between ten miRNAs (novel-m0778-3p, miR6135e.2-5p, miR477-3p, miR4416c-5p, miR946d, miR398b, miR389a-3p, novel m0068-5p, novel-m0650-3p, and novel-m0560-3p) and important target genes (auxin response factor-3, gretchen hagen-9, scarecrow-like-1, squamosa promoter-binding protein-like-12, small auxin upregulated RNA-70, binding protein-9, vacuolar invertase-1, starch synthase-3, sucrose synthase-3, probable starch synthase-3, cell wall invertase-4, and trehalose phosphatase synthase-5), all of which play a role in plant hormone signaling and starch and sucrose metabolism pathways. The quantitative polymerase chain reaction (qRT-PCR) was used to validate the relative expression of these miRNAs and their targeted genes. These results provide novel insights and a foundation for further studies to elucidate the molecular factors and processes controlling AR formation in woody plants.